U.S. patent application number 12/882024 was filed with the patent office on 2011-03-17 for semi bolt receiver assembly for assembly with a semi automatic rifle base.
Invention is credited to Robert Tyler Webb.
Application Number | 20110061523 12/882024 |
Document ID | / |
Family ID | 43729194 |
Filed Date | 2011-03-17 |
United States Patent
Application |
20110061523 |
Kind Code |
A1 |
Webb; Robert Tyler |
March 17, 2011 |
Semi Bolt Receiver Assembly for assembly with a Semi Automatic
Rifle Base
Abstract
A new and useful a semi bolt receiver assembly is provided, that
configured for assembly with a rifle base that has a buttstock and
pistol grip configured for semi automatic operation. The semi bolt
receiver assembly includes a receiver, a bolt and carrier assembly,
and a manually operable handle that is coupled with the bolt and
carrier assembly in a manner that enables the bolt and carrier
assembly to be manipulated by a shooter to charge the rifle (i)
while the shooter is maintaining a shooting position and (ii)
without removing the shooter's hand from the pistol grip. The semi
bolt receiver assembly is particularly useful when configured for
assembly with an AR-15 rifle base.
Inventors: |
Webb; Robert Tyler; (Arenas
Valley, NM) |
Family ID: |
43729194 |
Appl. No.: |
12/882024 |
Filed: |
September 14, 2010 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
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61276629 |
Sep 15, 2009 |
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Current U.S.
Class: |
89/128 |
Current CPC
Class: |
F41A 3/42 20130101 |
Class at
Publication: |
89/128 |
International
Class: |
F41C 7/00 20060101
F41C007/00 |
Claims
1. Apparatus comprising a semi bolt receiver assembly configured
for assembly with a rifle base that has a buttstock and pistol grip
configured for semi automatic operation, the semi bolt receiver
including a bolt and carrier assembly, and a manually operable
handle is coupled with the bolt and carrier assembly in a manner
that enables the bolt and carrier assembly to be manipulated by a
shooter to charge the rifle (i) while the shooter is maintaining a
shooting position and (ii) without removing the shooter's hand from
the pistol grip.
2. The apparatus of claim 1, wherein the handle and bolt and
carrier assembly are coupled and configured in a manner that
enables the operation of the manually operable handle in charging
the rifle to be substantially a straight pull action, while the
shooter is maintaining a shooting position.
3. The apparatus of claim 2, wherein the semi bolt receiver
assembly includes a receiver, and wherein the handle is coupled
with a handle mount that has a portion which extends through a side
opening in the receiver.
4. The apparatus of claim 3, wherein the semi bolt receiver
assembly is configured for assembly with an AR-15 rifle base.
5. The apparatus of claim 4, wherein the semi bolt receiver
assembly is configured to restrict diversion of a portion of
combustion gas that is generated when the rifle is being fired.
6. The apparatus of claim 4, wherein the semi bolt receiver
assembly includes a barrel that is configured without a gas port
for diverting a portion of combustion gas that is generated when
the rifle is being fired.
7. The apparatus of claim 4, wherein the portion of the receiver
assembly that has the side opening has a height of at least 2.25
inches
8. The apparatus of claim 1, wherein an adaptor base is coupled
with the bolt and carrier assembly, and the handle mount to which
the handle is coupled is connected to the adaptor base.
9. The apparatus of claim 7, wherein the adaptor base is coupled to
the bolt carrier, and the adjustable handle is coupled with the
handle mount in a manner that enables the length of pull of the
adjustable handle to be selectively adjusted over a predetermined
range.
10. The apparatus of claim 8, wherein the semi bolt receiver
assembly includes a receiver, and wherein the adjustable handle is
coupled with the handle mount in a manner that enables the handle
to be selectively manipulated relative to the side of the semi bolt
receiver to adjust the angle at which the handle is oriented
relative to the side of the semi bolt receiver.
11. The apparatus of claim 10, wherein the semi bolt receiver
assembly is configured for assembly with an AR-15 rifle base.
12. The apparatus of claim 1, wherein the bolt and carrier assembly
includes a bolt carrier with a substantially cylindrical
configuration, and wherein the adaptor base is connected with the
bolt carrier by one or more fasteners, each of which extends
through the adaptor base and into the top of the cylindrical bolt
carrier and directs forces applied to the adaptor base through the
cylindrical bolt carrier along a line of action extending through
the center of the cylindrical bolt carrier.
13. The apparatus of claim 12, wherein the semi bolt receiver
assembly is configured for assembly with an AR-15 rifle base.
14. Apparatus comprising a semi bolt receiver assembly configured
for assembly with a rifle base that has a buttstock and pistol grip
configured for semi automatic operation, the semi bolt receiver
assembly including a. a bolt and carrier assembly, b. an adaptor
base that is connected with the bolt and carrier assembly, c. a
manually operable handle that is coupled with the adaptor base in a
manner that enables the orientation of the handle relative to the
bolt and carrier assembly to be selectively adjusted to a plurality
of operating orientations relative to the bolt and carrier assembly
and in a manner that enables the handle to charge the bolt and
carrier assembly when the handle is in any of the plurality of
operating orientations, and d. a semi bolt receiver.
15. The apparatus of claim 14, wherein the bolt and carrier
assembly includes a bolt carrier with a substantially cylindrical
configuration, and wherein the adaptor base is connected with the
bolt carrier by a fastener that extends from the adaptor based
through the top of the cylindrical bolt carrier and directs forces
applied to the adaptor base through the cylindrical bolt carrier
along a line of action extending through the center of the
cylindrical bolt carrier.
16. The apparatus of claim 15, wherein the manually operable handle
is connected to a handle mount that is coupled to the adaptor base,
the connection between the handle and the handle mount configured
to enable the length of pull of the adjustable handle to be
selectively adjusted over a predetermined range.
17. The apparatus of claim 16, wherein the handle has a connector
portion that extends through and is supported in a sleeve that
forms part of the handle mount, and the handle has a hand grip
portion that extends at an angle to the connector portion, and
wherein connector portion can be selectively connected at different
locations along the sleeve, and at selected rotational orientations
in the sleeve, to selectively adjust the length of pull of the
handle, to selectively adjust the angle at which the hand grip is
oriented relative to the bolt and carrier assembly.
18. The apparatus of claim 17, wherein the handle and bolt and
carrier assembly are coupled and configured in a manner that
enables the operation of the manually operable handle in charging
the rifle to be substantially a straight pull action.
19. The apparatus of claim 18, wherein the semi bolt receiver has a
side slot, through which a portion of the handle mount carrying the
sleeve extends, so that the handle is located on a side of the
receiver, in a convenient orientation to be grasped by a shooter's
hand on that side of the receiver.
20. The apparatus of claim 15, wherein the semi bolt receiver is
configured for assembly with an AR-15 rifle base, and the portion
of the receiver carrying the side slot has a height of at least
2.25 inches
Description
Related Application/Claim of Priority
[0001] This application is related to and claims priority from U.S.
provisional application Ser. No. 61/276,629, filed Sep. 15, 2009,
entitled "Semi bolt action conversion adaptor for AR 15 rifle"
which provisional application is incorporated herein by
reference
INTRODUCTION, BACKGROUND AND SUMMARY OF THE PRESENT INVENTION
[0002] The present invention relates to a new and useful structure,
referred to herein as a "semi bolt receiver assembly" that is
designed to be coupled with semi automatic rifle base, e.g. the
lower portion (also referred to as a lower receiver) of a rifle of
the modular type which is well known in connection with a rifle
known as the AR 15. The type of semi automatic rifle base with
which the semi bolt receiver assembly of the present invention is
particularly useful would typically comprise a buttstock and pistol
grip configured for semi automatic operation, such that the
buttstock has a buffer spring that is compressed by movement of a
bolt and carrier assembly against a buffer when the rifle is being
discharged or unloading a spent round and causes the buffer to act
on a bolt carrier assembly (e.g. in the manner of a semi automatic
rifle) when the rifle is being charged or loaded.
[0003] The principles of the present invention are described herein
in connection with conversion of a semi automatic rifle base (e.g.
an AR15 semi automatic rifle base) to semi bolt-action operation
with the apparatus described herein, and from that description the
manner in which the principles of the present invention can be used
to convert similar types of rifle base, (e.g. AR 10 or SR 25
rifles) or create new rifles in accordance with those principles,
will be apparent to those in the art. In addition, the principles
of the present invention are particularly useful to produce an
upper receiver assembly that can be assembled with a rifle based
that is substantially conformable to the standards of existing AR
15/M16 rifle lower receivers.
[0004] In applying the principles of the present invention to a
semi automatic rifle base such as an AR 15 rifle, the purpose of
the invention includes:
[0005] 1) improving the accuracy of the rifle by converting the gas
operating system to manual operation;
[0006] 2) retaining a cartridge loading speed advantage over
convention bolt action rifles;
[0007] 3) eliminating the action fouling due to the gas operating
system of the semi automatic AR 15 rifle; and
[0008] 4) improving the ability to manipulate the bolt with the
least movement and effort.
[0009] The AR15 Rifle is one of the most versatile and affordable
rifle designs ever conceived and certainly the most modified and
adapted beyond its intended military use. In recent years it has
become the most widely used target rifle in certain competitive
disciplines and new dedicated variants appear frequently.
[0010] The rifle is divided into an upper and lower half (Exhibits
A1, A2). The lower half, connects to a buttstock, and contains the
pistol grip, the trigger mechanism and holds the ammunition. It is
the registered part of the rifle. The upper half, to which this
invention pertains, contains the bolt and carrier assembly, the
barrel, sights and special purpose attachments. It can be
configured in many ways. Because of its modular design it is
possible to have one lower half and many different upper halves
(sometimes called variants) each dedicated to a different type of
shooting or purpose because each will mate to the lower half. The
invention proposed herein was inspired primarily by a desire to
improve the performance of the rifle in the target shooting
disciplines but should have diverse appeal. It should be considered
a new variant because it has a dedicated design and function that
is distinctly different from any existing variants or any known
rifles known to applicant.
[0011] If the AR15 Rifle has a drawback, in the sport of target
shooting, it is the gas operated self-loading system that employs
parts that move during the shot process. It is an undesirable
characteristic that can affect accuracy and many top competitors
prefer to use a traditional or specialized bolt action rifles in
long-range events, bench rest competition, or varmint hunting; all
of which demand extreme accuracy. The bolt-action rifle operates
with a closed bolt throughout the firing process and causes no
disturbance to the rifle when it is fired. However, despite having
an edge in accuracy the bolt action rifle has its own drawbacks.
For example, in NRA "Match Rifle" competition there are two
separate rapid-fire stages in the match that are conducted at
different ranges and from different positions. Many shooters have
difficulty firing all the required shots accurately due to the time
it takes to manually operate the bolt; which must be raised to
unlock the bolt, pulled to extract the spent cartridge, pushed in
order to extract a cartridge from the magazine and chamber it, and
lowered in order to lock the bolt. Sometimes the shooter must raise
his head off the stock to avoid the retracting bolt. In the prone
position it is sometimes necessary to lift ones arm from the
shooting mat, in order to operate the bolt. The more expensive bolt
action competition rifles incorporate features designed to overcome
these drawbacks (in a manner different than the present invention)
but most shooters cannot afford them. All of these circumstances
cause the "position" of the shooter to break down. At these short
and middle range events, which are fired at 200 to 300 yards the
self-loading AR15 rifle enjoys an advantage because the shooter
does not have to manipulate a bolt. The same rifle must be used
across the entire course of fire.
[0012] When the match moves back to the 600-yard slow fire stage
the bolt-action rifle assumes an advantage because there are no
moving parts during the shot process. The scores at this stage
generally determine the winner of the match. With the recent
offering of improved cartridges and calibers for the AR15 the
bolt-action does not enjoy the complete dominance that it once had
at long range, but it is often preferred.
[0013] The invention described herein seeks to address the issue of
accuracy and retain most of the speed advantage enjoyed by the AR15
with a semi bolt-action configuration. It also has the added
benefit of a much cleaner action with less wear and requires less
lubrication and maintenance by way of eliminating the gas operating
system which fouls the action. It also makes it ergonomically
feasible to shoot accurately in timed shooting events that, until
now, have been impractical with other conversions. The application
is intended primarily for rifles that would normally employ an AR15
A3 style flattop upper receiver which often requires the use of a
scope, as in bench rest shooting, or sophisticated iron sights as
in NRA Match Rifle competition. It will easily adapt to other
disciplines as well.
[0014] In accordance with the present invention, a semi bolt
receiver assembly is configured for assembly with a rifle base that
has a buttstock and pistol grip configured for semi automatic
operation. The semi bolt receiver assembly includes a bolt and
carrier assembly, and a manually operable handle is coupled with
the bolt and carrier assembly in a manner that enables the bolt and
carrier assembly to be manipulated by a shooter to charge the rifle
(i) while the shooter is maintaining a shooting position and (ii)
without removing the shooter's hand from the pistol grip.
Preferably, the handle and bolt and carrier assembly are coupled
and configured in a manner that enables the operation of the
manually operable handle in charging the rifle to be substantially
a straight pull action, while the shooter is maintaining an
undisturbed shooting position.
[0015] The concept of a rifle base that is configured for semi
automatic operation means that the rifle base has an attached
buttstock and pistol grip configured for semi automatic operation
means, in that the buttstock has a buffer spring that is compressed
when the rifle is being discharged or unloaded and acts on a buffer
to move the bolt carrier assembly in the manner of a semi automatic
rifle when the rifle is being charged or loaded.
[0016] In a preferred embodiment, the manually operable handle is
coupled with an adaptor base in a manner that enables the length of
pull of the adjustable handle to be selectively adjusted over a
predetermined range. In addition, the handle is coupled with the
adaptor base in a manner that the handle extends at an angle to the
bolt and carrier assembly and allows the handle to be selectively
manipulated to adjust the angle at which the handle is oriented
relative to the bolt and carrier assembly. The connection between
the handle and the bolt and carrier assembly is preferably
configured in a manner that enables the operation of the manually
operable handle in charging the rifle to be substantially a
straight pull action by a shooter, along a side of the receiver, in
a convenient orientation to be grasped by a shooter's hand on that
side of the receiver.
[0017] Also, the bolt and carrier assembly includes a bolt carrier
with a substantially cylindrical configuration, and the adaptor
base is connected with the bolt carrier by one or more fasteners
that extend from the adaptor base through the top of the
cylindrical bolt carrier and directs forces applied to the fastener
from the top of the cylindrical bolt carrier downward along a line
of action extending through the center of the cylindrical bolt
carrier. Thus, the line of action of forces on the bolt and carrier
assembly is through a relatively strong section of the bolt and
carrier assembly, which is designed to minimize the risk of
breakage of components when the rifle is being manipulated and
fired.
[0018] Thus, a rifle with a semi bolt receiver assembly configured
according to the principles of the present invention, is designed
to enable a shooter to recharge the bolt and carrier assembly while
maintaining a shooting position and without removing the shooter's
hand from the pistol grip. This enables the shooter to have the
accuracy normally provided by a bolt action rifle, and the speed of
firing that is normally associated with a semi automatic rifle such
as the AR 15. The principles of the present invention are
particularly useful in configuring a semi bolt receiver assembly
that can be assembled with a rifle base or lower receiver that is
substantially conformable to the standards of existing AR15/M16
rifles.
[0019] These and other features of the present invention will
become further apparent from the following detailed description,
and the accompanying drawings and exhibits.
Brief Description of the Drawings and Exhibits
[0020] FIG. 1 is a schematic illustration of a shooter in a firing
position with a rifle having semi bolt receiver assembly, according
to the principles of the present invention;
[0021] FIG. 2 is an enlarged, schematic illustration of a portion
of the rifle having the semi bolt receiver assembly according to
the principles of the present invention;
[0022] FIG. 3 is an exploded view of components forming the semi
bolt receiver assembly, according to the principles of the present
invention;
[0023] FIG. 4 is a schematic illustration of the semi bolt receiver
assembly according to the principles of the present invention, in
one of its operational positions;
[0024] FIG. 5 is a side view of a modified configuration of an
adaptor base, handle and handle mount, for a semi bolt receiver
assembly, according to the principles of the present invention;
[0025] FIG. 6 is a top view of the modified configuration of FIG.
5;
[0026] FIG. 7 is a side view of a portion of the receiver, for the
modified configuration of FIG. 5; and
[0027] FIG. 8 is a rear view of the modified configuration of FIG.
5.
[0028] Exhibit A1 is an exploded view of the primary components of
an AR 15 rifle, Exhibit A2 is a detailed exploded view, and parts
list for an AR 15 rifle, Exhibit A3 illustrates how when the
principles of the present invention are used to modify an existing
AR 15 rifle, the adaptor base of the present invention prevents the
bolt from closing if the gas tube of the AR 15 is not removed,
and
[0029] Exhibits B-D are views of a shooter operating a rifle with
an AR 15 rifle base, and a semi bolt receiver assembly configured
according to the principles of the present invention.
DETAILED DESCRIPTION
[0030] As described above, the present invention relates to a new
and useful structure, referred to herein as a "semi bolt receiver
assembly" that is designed to be coupled with a modular type rifle
base, which is well known in connection with a rifle known as the
AR 15. In a typical AR 15 rifle, the primary components are a
magazine 1, bolt carrier assembly 3, charging handle 4, upper
receiver and barrel assembly 5, and lower receiver and buttstock
assembly 6 (see Exhibit A1). The semi bolt receiver assembly of the
present invention would replace the upper receiver and barrel
assembly. The coupling between the semi bolt receiver assembly of
the present invention and the lower receiver and buttstock assembly
6 would typically comprise takedown or pivot pins that are shown at
77 and 61 in Exhibit A2.
[0031] The principles of the present invention are described herein
in connection with conversion of a typical AR15 semi automatic
rifle to semi bolt-action operation with the semi bolt receiver
assembly described herein. Also, Exhibit A2 shows an exploded view
and parts list for an AR 15 rifle, and wherever possible in this
description, where a component that is described herein is
essentially the same as the part of Exhibit A1 or Exhibit A2,
applicant has sought to retain the numbering scheme of Exhibits A1
and A2. Where a component is either not shown in Exhibits A1 or A2,
or is different from a component of those exhibits, on account of
that component being configured in accordance with the principles
of the present invention, applicant has adopted a numbering scheme
different from the parts lists of Exhibits A1 and A2. In addition,
in the course of this detailed description, applicant has described
existing rifles known to applicant and the manner in which a rifle
with the applicant's semi bolt receiver assembly both differs from
those existing rifles, and is also believed to provide advantages
in relation to those rifles. From that description the manner in
which the principles of the present invention can be used to
convert rifles similar to the AR 15, or create new rifles in
accordance with those principles, will be apparent to those in the
art.
[0032] According to the present invention a semi bolt receiver
assembly 100 (FIG. 3) is configured for assembly with a rifle base
102 that has a buttstock 104 (of conventional design as shown as
part of the lower receiver and Buttstock assembly 6 shown in
Exhibit A1) and pistol grip 74 (also of conventional design, see
e.g. Exhibit A2). The rifle base 102 has a trigger 65, a buffer
spring 41 and a buffer 42 (piston), that are of conventional design
(see e.g. Exhibit A2) and is configured for semi automatic
operation, in the sense that when the rifle discharges a spent
cartridge, by pulling the charging handle that is described herein,
the buffer spring 41 is compressed, and when the charging handle
120 (described further herein) is released, the buffer spring 41
causes the buffer 42 to act on a bolt and carrier assembly
(comprising a carrier 31 and a bolt 33, as shown in Exhibit A2), to
strip and (schematically shown in FIG. 4), and insert a new
cartridge from a magazine (shown at 1 in Exhibit A1).
[0033] According to the principles of the present invention, the
semi bolt receiver assembly 100 has a manually operable handle 120
that is coupled with the bolt and carrier assembly, in a manner
that enables the bolt and carrier assembly to be manipulated by a
shooter to charge the rifle (i) while the shooter is maintaining a
shooting position and (ii) without removing the shooter's hand from
the pistol grip 74. The bolt and carrier assembly is of a
conventional configuration, e.g. comprising a bolt carrier 31 and
bolt 33 as shown in Exhibit A2 and in the Figures. The handle 120
is coupled with the bolt carrier assembly, in a manner described
herein, such that the operation of the manually operable handle 120
in charging the rifle is a substantially a straight pull action,
while the shooter is maintaining a shooting position.
[0034] Thus, as seen in FIG. 1, and in Exhibits B-D, a shooter is
holding a rifle with a semi automatic base (e.g. comprising
Buttstock 104, trigger 65 and pistol grip 74) and a semi bolt
receiver assembly 100 according to the principles of the present
invention. In Exhibit B, the shooter is squeezing the trigger to
fire the rifle. In Exhibit C, the shooter is pulling the handle 120
to discharge a spent cartridge from the rifle, and as shown in
Exhibit C, as the shooter is pulling the handle, the shooter's hand
remains on the pistol grip 74. In Exhibit D, the shooter has
released the handle 120, but (although not shown) the shooter's
thumb remains about the pistol grip 74. As the handle 120 is
released, the buffer spring 41 causes the buffer 42 to act on the
bolt and carrier assembly to strip (see FIG. 4) and load (insert) a
new cartridge from the magazine (1 in Exhibit A1) into the rifle
chamber, in position to be fired. Thus, as will be appreciated by
those in the art, the rifle according to the present invention
provides the bolt action as the handle is pulled, is like a bolt
action rifle in that there is no diversion of combustion gas when
the rifle is fired and has the semi automatic rifle feature of
utilizing the buffer spring 41 and buffer 42 to act on the bolt and
carrier assembly when the handle 120 is released, to strip and
insert a new cartridge, in the manner of a semi automatic
rifle.
[0035] In the semi bolt receiver assembly 100 of the present
invention, the manually operable handle 120 is coupled with a
handle mount 122 that has a portion which extends through a side
opening 123 in a web portion 125 of a receiver 101 that forms part
of the semi bolt receiver assembly 100. The height H of that
portion of the receiver 101 that includes the web 125 is preferably
at least 2.25 inches (see FIG. 7), to enable the handle 120 to be
supported in the manner described further herein, and to be located
in a convenient manner to enable a shooter to operate the rifle in
the manner illustrated in Exhibits B-D.
[0036] When the semi bolt receiver assembly 100 is configured by
modifying an existing AR 15 type upper half, the semi bolt receiver
assembly is configured to restrict diversion of a portion of
combustion gas that is generated when the rifle is being fired.
This can be done, e.g. by providing a barrel band 124 (FIG. 1) that
covers the gas diversion port in the AR 15 rifle barrel (and also
by removing the gas tube 4 (Exhibit A2), because the adaptor base
is configured such that in the presence of a gas tube the bolt
cannot close and the rifle cannot fired, so that the gas tube shown
at 4 in Exhibit A2 must be removed, as will be further appreciated
from Exhibit A3). On the other hand, if a receiver assembly is
configured to operate according to the principles of for the
present invention, rather than modifying an existing AR 15 type
receiver, the semi bolt receiver assembly shown in FIG. 1 would
have a barrel that is configured without a gas port for diverting a
portion of combustion gas that is generated when the rifle is being
fired.
[0037] In assembling a semi bolt receiver assembly 100, according
to the principles of the present invention, an adaptor base 130 is
coupled with the bolt and carrier assembly, which are contained by
the semibolt receiver 101, and the handle mount 122 (to which the
handle 120 is coupled) is connected to the adaptor base.
Specifically, the handle mount 122 includes a sleeve 122a that is
fixed to a coupling portion 122b which, in turn is fastened to the
adaptor base 130 (e.g. by one or more cap head screws that extend
through openings 127 in the adaptor base). The adaptor base 130 is
coupled to the bolt carrier 31, and the adjustable handle 120 is
coupled with the handle mount 122 in a manner that enables the
length of pull of the adjustable handle 120 to be selectively
adjusted over a predetermined range. Also, adjustable handle 120 is
coupled with the handle mount 122 in a manner that enables the
handle to be selectively manipulated relative to the connection
portion to adjust the angle at which the handle is oriented
relative to the side of the semi bolt receiver 100. It should also
be noted that the receiver assembly may have a pair of sights 140,
142 that would be of conventional design, where the sight 140 may
be connected to a weaver rail 144 that would also be of
conventional design.
[0038] Specifically, the handle 120 comprises a relatively straight
portion 120a, and a portion 120b that extends at an angle to the
straight portion 120a. The straight portion 120a is received in the
sleeve 122a of the handle mount in a manner that enables the handle
to slide relative to the handle mount and to rotate (pivot) in the
sleeve 122a. The handle can be locked in a selected position for
adjusting the pull length of the handle, by a set screw 136 and can
be locked in a selected rotational (angular) orientation by a clamp
nut 138 that can be tightened about the handle portion 120a. This
allows both the length of pull of the handle, and the angular
orientation of the handle relative to the receiver 101 to be
selectively adjusted. In addition the handle has a knob 120c that
is adjustable for height in order to accommodate hand size and
individual style of gripping the rifle (see e.g. FIG. 8).
[0039] In another aspect of the present invention, the bolt carrier
31 has a substantially cylindrical configuration (as is known), and
the adaptor base 130 is connected with the bolt carrier by one or
more fasteners 141 (see FIGS. 3 and 8), each of which extends
through the adaptor base and into the top of the cylindrical bolt
carrier 31. Thus, forces applied to the adaptor base 130 are
directed through the cylindrical bolt carrier are along a line of
action extending through the center of the cylindrical bolt carrier
31. In essence, as those in the art will appreciate, the adaptor
base 130 is coupled to the bolt carrier in a manner that it
replaces the bolt carrier key 28 of the conventional bolt carrier
assembly of Exhibit A2. That enables the adaptor base 130 to be
coupled to the bolt carrier at a relatively strong location, and to
channel forces applied from the handle along a line of action that
is substantially downward along a line of action through the center
of the cylindrical bolt carrier 31. Such a coupling is designed to
minimize the risk of the connection between the handle 120 and the
bolt carrier assembly from breaking or becoming deformed as the
handle is being repeatedly operated.
[0040] Thus, as will also be appreciated by those in the art, with
a semi bolt receiver assembly according to the present invention,
assembled with rifle base that has a buttstock and pistol grip
configured for semi automatic operation, the connection between the
handle and the bolt and carrier assembly enables the orientation of
the handle relative to the bolt and carrier assembly to be
selectively adjusted to a plurality of operating orientations
relative to the bolt and carrier assembly and in a manner that
enables the handle to charge the bolt and carrier assembly when the
handle is in any of the plurality of operating orientations. The
connection between the handle and the bolt and carrier assembly is
designed to enable the shooter to charge the rifle with a straight
pull action, and without removing the shooter's hand from the
pistol grip of the rifle. This enables relatively rapid firing of
the rifle, in a manner that is like that of a semi automatic rifle,
but avoids the various issues that are described herein that result
from the diversion of combustion gas that is associated with
operation of a semi automatic rifle.
[0041] In the modification shown in FIGS. 5-8, the adaptor base 130
has a slightly different configuration than that shown and
described in FIG. 3, but retains the features described above, in
terms of providing a relatively strong coupling between the handle
120 and the bolt and carrier assembly, and in providing for
adjustment of the pull length of the handle and the angular
position of the handle. In addition, FIG. 7 illustrates the added
height of the receiver 101, in the extended web area 125 that
accommodates the slot 123 for the handle, and the manner in which
that added height is used to provide the handle in a convenient
operating position, in accordance with the principles of the
present invention. Specifically, as shown in FIG. 7, the added
height of the receiver 101 is provided in the web portion 125 that
adds about 1/2 inch to the overall height of the receiver 101
(compared to a standard A3 receiver), so that the receiver 101 is
at least about 2.25 inches in overall height. That added web
portion carries the slot 123, and the handle mount 122 has a
portion 122c extends through that slot, so that the handle mount
sleeve 122a into which the handle portion 120a fits is located on a
side of the receiver 100, and the handle portion 120b extends
angularly downward relative to the receiver at a convenient angle
to be grasped by a shooter and operated in the manner described
herein.
[0042] It is believed the following description will further enable
those in the art to appreciate the structure and operation of the
semi bolt receiver assembly of the present invention.
[0043] The AR15 Rifle is one of the most versatile and affordable
rifle designs ever conceived and certainly the most modified and
adapted beyond its intended military use. In recent years it has
become the most widely used target rifle in certain competitive
disciplines and new dedicated variants appear frequently.
[0044] The rifle is divided into an upper and lower half (Exhibits
A1, A2). The lower half contains the trigger mechanism and holds
the ammunition. It is the registered part of the rifle. The upper
half, which this invention concerns, contains the bolt and carrier
assembly, the barrel, sights and special purpose attachments. It
can be configured in many ways. Because of its modular design it is
possible to have one lower half and many upper halves each
dedicated to a different type of shooting or purpose because each
will mate to the lower half. The invention proposed herein was
inspired primarily by a desire to improve the performance of the
rifle in the target shooting disciplines but should have diverse
appeal.
[0045] If the AR15 Rifle has a drawback, in the sport of target
shooting, it is the gas operated self-loading system that employs
parts that move during the shot process. It is an undesirable
characteristic that can affect accuracy and many top competitors
prefer to use a traditional or specialized bolt action rifles in
long-range events, bench rest competition, or varmint hunting; all
of which demand extreme accuracy. The bolt-action rifle operates
with a closed bolt throughout the firing process and causes no
disturbance to the rifle when it is fired. However, despite having
an edge in accuracy the bolt action rifle has its own drawbacks.
For example, in NRA "Match Rifle" competition there are two
separate rapid-fire stages in the match that are conducted at
different ranges and from different positions. Many shooters have
difficulty firing all the required shots accurately due to the time
it takes to manually operate the bolt; which must be raised to
unlock the bolt, pulled to extract the spent cartridge, pushed in
order to extract a cartridge from the magazine and chamber it, and
lowered in order to lock the bolt. Sometimes the shooter must raise
his head off the stock to avoid the retracting bolt. In the prone
position it is sometimes necessary to lift ones arm from the
shooting mat, in order to operate the bolt. The more expensive bolt
action competition rifles incorporate features that overcome these
drawbacks but most shooters cannot afford them. All of these
circumstances cause the "position" of the shooter to break down. At
these short and middle range events, which are fired at 200 to 300
yards the self-loading AR15 rifle enjoys an advantage because the
shooter does not have to manipulate a bolt. The same rifle must be
used across the entire course of fire.
[0046] When the match moves back to the 600-yard slow fire stage
the bolt-action rifle assumes an advantage because there are no
moving parts during the shot process. The scores at this stage
generally determine the winner of the match. With the recent
offering of improved cartridges and calibers for the AR15 the
bolt-action does not enjoy the complete dominance that it once had
at long range, but it is often preferred.
[0047] The invention described herein seeks to address the issue of
accuracy and retain most of the speed advantage enjoyed by the AR15
with a semi bolt-action configuration. It also has the added
benefit of a much cleaner action with less wear and requires less
lubrication and maintenance by way of eliminating the gas operating
system which fouls the action. It also makes it ergonomically
feasible to shoot accurately in timed shooting events that until
now have been impractical with other conversions. The application
is intended primarily for rifles that would normally employ an AR
15 A3 flattop upper receiver (Exhibits B-D) which often requires
the use of a scope, as in bench rest shooting, or sophisticated
iron sights as in NRA Match Rifle competition. It may be adaptable
to other variants as well. The principles of the present invention
are particularly useful in configuring a semi bolt receiver
assembly that can be assembled with a rifle base or lower receiver
that is substantially conformable to the standards of existing
AR15/M16 rifles, as will be clear to those in the art.
[0048] When a shot is fired in an unmodified AR15 Rifle, gas
pressure from the propellant pushes the bullet down the barrel as
in any other rifle. At a point approximately two thirds of the way
down the barrel is a small gas port manifold that bleeds off a
small portion of combustion gas as the bullet passes the hole. This
gas is partially expelled into the action through a gas tube
rearward to the rifle action where it enters the carrier key that
sits atop the bolt carrier. The carrier key (Exhibit A2) diverts
the gas to the inside and back of the bolt recess The carrier
acting as a barrier to the gas, is pushed rearward which, via a cam
pin, causes the bolt to unlock from the chamber and begin the
extraction of the spent cartridge. When the bolt carrier has
reached its rearmost position the spent cartridge is ejected and
gas is expelled into the action. Simultaneously the bullet exits
the barrel. The bolt carrier has compressed a buffer spring,
located in the buttstock of the rifle, which then pushes the bolt
and carrier assembly forward. A cartridge is stripped from the
magazine, is chambered, and the bolt is closed via the bolt cam
pin. The rifle is ready to fire again. It is this movement of the
bolt and carrier during the firing process that leads to
inaccuracy. It also leads to fouling of the action that is
undesirable in any rifle much less one used for competition.
[0049] In a retrofit application the semi-bolt conversion is
accomplished by first removing the gas tube and manifold and then
covering the hole with a barrel band (see e.g. FIG. 1) that is
secured to the barrel either by a setscrew or adhesive. This will
prevent any gas from escaping except from the muzzle of the barrel.
This operation is only necessary when converting existing barrels.
New barrels can be manufactured without the gas port; thereby
eliminating the need for the barrel band.
[0050] All the remaining steps are common to retrofit and new
manufacture upper halves. A newly designed, taller, upper receiver
assembly (FIG. 7) is employed in order to facilitate the use of a
semi-bolt action adapter base and side-charging handle (FIGS. 1-4,
Exhibits B-D). Near the top of the receiver assembly a slot milled
into the web under the sight rail, in order to accept the handle
assembly which attaches to the base (FIG. 7). The adapter base is
composed of a mild steel block that is attached by screws to the
standard bolt carrier and replaces the carrier key and the charging
handle (shown at 4 in Exhibit A1). The side-charging handle 120 of
the present invention, which is adjustable, is attached to the
adapter base, and is parallel to the side of the receiver. As a
safety feature, the forward portion of the adapter base prevents
the bolt from closing if a gas tube is present (see Exhibit A3),
thereby requiring removal of the gas tube when a receiver assembly
according to the present invention is being retrofitted to an
existing AR 15.
[0051] The operation of the rifle is much the same as before the
modification. All safety features remain in place. When a cartridge
is fired the bolt remains closed without disturbing the rifle. The
shooter extracts the round at his or her discretion by simply
pulling back on the bolt handle to its rearmost position. The bolt
cam pin rotates as before. The bolt carrier goes to the rear as
before, the buffer spring is compressed, and the spent cartridge is
ejected. But no gas is expelled (diverted) during that action and
it took about one second. To charge the rifle again only involves
releasing the bolt handle. The buffer spring advances the bolt and
carrier, strips the cartridge from the magazine, chambers the round
and closes the bolt via the bolt cam (shown in Exhibit A2). The
rifle is ready to fire. The extraction, ejection, and charging of
the rifle is accomplished in a single motion. The shooter does not
have to make four separate acts to operate the bolt. Neither did he
have to remove his hand from the pistol grip of lift his elbow.
Adjustability is essential to facilitate the least movement of the
firing hand which minimizes deterioration of position. That is
accomplished by the bolt handle which is adjustable for length of
pull, height, and angle. More time is gained to reacquire the sight
picture, sight alignment, and trigger control than is possible for
bolt-action shooters in rapid-fire stages. At longer ranges,
shooters benefit from the fact that the rifle undergoes no cycling
induced movement during the shot due to the elimination of the gas
operation of the bolt. All shooters will benefit from not having to
clean dirty deposits from their actions.
[0052] I have called it a semi-bolt action because after the
conversion it is no longer a semi-automatic, but neither is it a
true bolt-action. Properly speaking it would be, by default, a
spring assisted straight pull action design. The straight pull
action design has been around for nearly 100 years and was first
widely employed in the Swiss K31 military rifle. Until the advent
of semi-auto rifles the K31 straight pull rifle was the fastest
manually loaded rifle available. It ejected the spent round and
cocked the rifle on the rearward stroke and stripped a new round
and chambered it on the forward stroke. Nearly all semi-auto and
automatic rifles employ some form of gas assisted extraction and
spring assisted loading variation of a straight pull design.
[0053] Other attempts to modify the AR15 to bolt action were
primarily inspired in Great Britain where semi-auto rifles are
restricted. Competitive shooters had to find ways to disable the
self loading aspects of their rifles in order to compete legally.
Bradley Arms offers a "bolt action" AR15 for sale in the UK that
employs a side charging handle which attaches to the sidewall of
the bolt carrier. In the U.S. various companies have used this
method in bolt action and semi-auto as well. All of them involve
threading a stud of some sort into the sidewall of the bolt carrier
and notching the receiver to some degree. Neither the receivers or
the bolt carriers were designed for this type of modification and
there is a history of bolts and or studs breaking in some versions.
Some of the receiver cuts are so extreme that it is hard to imagine
they do not undermine the integrity of the receiver. All of them
give the appearance of being an afterthought and most designs leave
a hole where the original charging handle has been eliminated.
(photo 1).
[0054] Due to the bolt carrier being several inches above the
pistol grip, and the sidewall of the bolt carrier having only
3/16'' purchase, the side of the bolt carrier is a poor location
for the kind of leverage and strain that are introduced by the bolt
handle. It was not intended for that. Some conversions appear to be
attempting the same thing as the semi-bolt design but cannot fully
incorporate the vertical component of the bolt handle due to the
extreme leverage against the bolt carrier. The shooter cannot reach
the handle without lifting the hand from the grip. The single point
attachment at the front of the bolt carrier, combined with the long
reach of the bolt handle, makes it impossible to have the
sufficient vertical drop on the handle that would enable one to
manipulate the bolt without causing undue strain. It was necessary
for me to address this problem early on in the testing of my own
design and it led me to shy away from the obvious drawbacks of
attaching to the side of the bolt carrier and skeletonizing the
sidewall of the receiver. It became necessary to redesign the
receiver in order to retain its strength and to take advantage of
the existing mortise and mounting holes on the top of the bolt
carrier that become available when the gas key is removed. This
method places the strain at the strongest part of the receiver;
where it is contained by the web under the sight rail. This
resulted in raising the sight rail by 1/2'' and had the added
benefit of improving the sight picture for most shooters. In
addition it provided more height and surface area in order to
resist rotational leverage against the bolt carrier and maintain
its proper alignment.
[0055] The semi-bolt method includes a built in safety feature that
other conversions do not. The base adapter is extended so that when
it is coupled with the bolt and carrier assembly, in the manner
described herein, in the presence of a gas tube the bolt cannot
close and the rifle cannot fire. The proposed receiver design
contains no hole for the gas tube and the millwork to accommodate
the original charging handle has been eliminated. The semi-bolt
system will not allow the simultaneous use of gas system parts;
specifically the gas carrier key and the gas tube. Conversions
which use a standard receiver and mount a handle on the side of the
carrier are capable of being reconverted to semi auto. This causes
a dangerous condition when a left handed person shoots a right
handed gun that has a handle which extends to the rear. If an
extended handle is present on a semi auto gun it is possible for
the shooter to be hit in the face by the handle. No such danger
exists with the semi-bolt system because it is a dedicated single
shot system with integral safety features which if removed will
essentially disable the gun.
[0056] Being that the AR15 is a modular platform very few
specialized tools are required to build or modify a rifle. Many
shooters prefer to build, rebarrel and modify their riffles
themselves. For that reason retrofit kits could be offered to
shooters and gunsmiths. These would include the receiver, adapter
base, a handle particular to the desired shooting discipline, and
the barrel band to block the gas if necessary. Complete upper
halves could be offered as well as complete rifles.
[0057] Commercially viability is almost certain. The proliferation
of AR15 variants in recent years continues unabated. A well thought
out, user friendly, bolt action would have appeal in several
different aspects of the shooting sports. For example: a bolt
action AR15 would overcome the stigma of it being a rifle suitable
only for military use and target shooting. There is a prejudice
against semi-auto rifles being used for game hunting because it is
considered unsporting to shoot anything but a bolt action. Some
major firearms manufacturers have semi auto hunting variants
available but it is uncertain whether they have made significant
inroads on the market. A bolt action AR15 upper might appeal to
those who already own an AR but hunt with traditional bolt action
rifles. An immediate niche would be found in Highpower Rifle
competition for the reasons previously explained. In addition the
improved utility of the semi-bolt design will inspire many to
upgrade their current conversions to the new design.
[0058] The semi-bolt conversion enables one to dry fire practice
sequential fire stages of a match. Dry firing is a practice
technique where the shooter, using dummy rounds, fires the gun in
order to develop sight alignment, trigger control, position, and
timing. Semi-auto shooters cannot dryfire practice the ten shot
strings of a rapid fire because the dummy rounds cannot actuate the
bolt cycle.
[0059] Already there exists in Great Britain a market for bolt
action AR15 rifles. In varmint hunting the AR is already very
popular and would be even more so if greater accuracy can be
obtained. The same is true for benchrest shooting where semi auto
rifles are unable to compete at the championship level. The
semi-bolt variant design would fill a long standing void in the
evolution of the AR15 rifle.
[0060] Thus, as seen from the foregoing detailed description, the
present invention provides a new and useful concept that provides a
semi bolt action receiver assembly that is configured for assembly
with a semi automatic rifle base, to retain the speed of operation
of a semi automatic rifle, while also provide the ease of operation
and accuracy features of a bolt action rifle. With the foregoing
description in mind, it is submitted that the manner in which such
genre of semi bolt action receiver assemblies can be produced, or
retrofit to existing semi automatic rifle bases, will be apparent
to those in the art.
* * * * *