U.S. patent application number 14/681031 was filed with the patent office on 2016-01-07 for post barrel plenum operated gas cycling system for automatic firearms.
The applicant listed for this patent is Klint McLean KINGSBURY, Clayton Warren REINARZ, Ronald Christopher SNIDER. Invention is credited to Klint McLean KINGSBURY, Clayton Warren REINARZ, Ronald Christopher SNIDER.
Application Number | 20160003565 14/681031 |
Document ID | / |
Family ID | 55016758 |
Filed Date | 2016-01-07 |
United States Patent
Application |
20160003565 |
Kind Code |
A1 |
KINGSBURY; Klint McLean ; et
al. |
January 7, 2016 |
Post Barrel Plenum Operated Gas Cycling System for Automatic
Firearms
Abstract
A gas buffer plenum positioned at the end of the barrel of an
automatic firearm. A barrel side end cap connects the system to the
barrel. A plenum tube holds one or more chamber walls and retains
gas pressure within the enclosure. A target side end cap creates
the final pressure chamber enclosure and is attached to the plenum
tube to lock the system together. This gas buffer plenum allows a
bullet to leave the barrel of the firearm before the bolt of the
firearm starts to open. As the gas buffer plenum is filled with the
exploding gas behind the bullet, the gas chambers build and
maintain pressure that is then forced back through a hole in the
plenum. The gas is forced down a gas tube or into a piston system.
Depending on the configuration of the firearm, either the gas
force, or the piston, strikes the bolt and cycles the firearm. The
system may also be used to retrofit a gas operated firearm that
uses a traditional gas block design.
Inventors: |
KINGSBURY; Klint McLean;
(Austin, TX) ; REINARZ; Clayton Warren; (New
Braunfels, TX) ; SNIDER; Ronald Christopher; (New
Braunfels, TX) |
|
Applicant: |
Name |
City |
State |
Country |
Type |
KINGSBURY; Klint McLean
REINARZ; Clayton Warren
SNIDER; Ronald Christopher |
Austin
New Braunfels
New Braunfels |
TX
TX
TX |
US
US
US |
|
|
Family ID: |
55016758 |
Appl. No.: |
14/681031 |
Filed: |
April 7, 2015 |
Related U.S. Patent Documents
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Application
Number |
Filing Date |
Patent Number |
|
|
61975987 |
Apr 7, 2014 |
|
|
|
Current U.S.
Class: |
89/194 |
Current CPC
Class: |
F41A 5/28 20130101; F41A
5/26 20130101 |
International
Class: |
F41A 3/62 20060101
F41A003/62 |
Claims
1. A gas buffer plenum positioned at the end of a firearm barrel to
collect, store and direct high pressure gas through a gas tube back
to a receiver of the firearm to cycle a bolt of the firearm after
the bullet has exited the barrel, the gas buffer plenum comprising:
(a) a plenum enclosure having a barrel oriented end and a target
oriented end; (b) a barrel side wall on the barrel oriented end of
the plenum enclosure, the barrel side wall comprising: (i) a center
axis barrel collar attachable to the end of the barrel of the
firearm; (ii) a center axis bullet inlet port; and (iii) an offset
return gas port; (c) a target side wall on the target oriented end
of the plenum enclosure, the target side wall comprising a center
axis bullet exit port; and (d) at least one chamber wall positioned
within the plenum enclosure between the barrel side wall and the
target side wall, the at least one chamber wall comprising a center
axis bullet pass through port and a concentric buffer wall
collecting, storing, and redirecting expanding gas from behind a
passing bullet back from the plenum enclosure to the offset return
gas port of the barrel side wall; wherein the expanding gas is
directed through the return gas port into a gas tube and is
conducted to the receiver of the firearm to cycle the bolt.
Description
CROSS REFERENCES TO RELATED APPLICATIONS
[0001] This application claims the benefit under Title 35 United
States Code .sctn.119(e) of U.S. Provisional Application
61/975,987, filed Apr. 7, 2014, the full disclosure of which is
incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to firearms and more
specifically to automatic gas operated firearms. The present
invention provides a gas buffer plenum at the end of a firearm
barrel that stores and directs high pressure gas through a gas tube
to the receiver of the firearm in order to cycle the bolt after the
bullet has left contact with the barrel rifling.
[0004] 2. Description of the Related Art
[0005] Most currently available automatic gas operated firearms
have a barrel with a small hole drilled vertically into the barrel
to allow gas to escape up into a gas block. This vertical hole and
gas block are typically located midway down the barrel. As a round
is fired, the explosion forces the bullet down the barrel and past
this small hole. As the bullet passes the hole, the still burning
gun powder and gas are forced up through the small hole and into
the gas block which directs the burning powder and gas in the
opposite direction down a gas tube and back into the receiver of
the firearm. Inside the receiver, the burning powder and gas impact
the bolt and force it backwards to eject the spent round casing and
load the next round. The balance of the burning powder and gas
continue their reaction and expand down the remainder of the
barrel, forcing the bullet out of the end and on down range.
[0006] Four issues result from the above described process. First,
the small vertical port hole creates an inconsistency in the bullet
path that can add vibration to the bullet. Vibration degrades
accuracy. Second, the gas pulled from the barrel to cycle the bolt
generates inconsistent gas pressure on the bullet as the bolt opens
while the bullet is still in contact with the barrel rifling. This
also degrades accuracy. Third, due to the midpoint position of the
vertical port hole, the powder from the round is not completely
burned up inside the barrel. As such, unburnt powder enters into
the gas tube and thereafter into the receiver and into the bolt
mechanism. This unburnt powder can cause the bolt mechanism to foul
faster and require more frequent cleaning for proper function.
Fourth, the gas forces on the bolt vary greatly depending on port
hole size, port hole position, and the length of the barrel.
Therefore, for a given round and the same gas block, a short barrel
might not correctly cycle the round while a longer barrel would, or
the reverse could be true. This last issue creates the need for
adjustable gas blocks that must be tuned precisely for each type of
round.
SUMMARY OF THE INVENTION
[0007] The present invention does not require a vertical port hole
in the barrel. This eliminates the inconsistency in the barrel and
reduces bullet vibration, thus adding accuracy. The gas port hole
is instead located in the buffer plenum of the present invention,
past the end of the barrel rifling. The bullet leaves the rifling
before the gas enters the plenum and is thereafter directed down
the gas tube. The bullet is no longer in contact with rifling when
the gas is drawn away and directed to the receiver and bolt. The
bolt starts to open after the bullet is out of rifling contact.
This allows for consistent gas pressure on the bullet throughout
barrel travel on every shot. Consistent gas pressure generates
consistent velocity and thus adds accuracy. Because the gas port
hole is located in the buffer plenum of the present invention, past
the end of the rifling, the system allows for more of the powder to
be burned before it is directed to the bolt. This reduces fouling
and allows for longer operation between cleanings.
[0008] The buffer plenum of the present invention has multiple
chambers. This causes the plenum to act like a capacitor as the
bullet travels through. The multiple chambers store pressure that
is consistently applied into the gas tube and to the bolt as the
bullet passes through the chambers. This greatly reduces cycling
issues with different rounds and barrel lengths. The end of barrel
gas buffer plenum of the present invention is an improvement on the
typical gas cycling mechanism for automatic firearms. Current gas
operated repeating firearms do not offer the same accuracy and
velocity as do bolt action firearms. The present invention allows
the same or similar accuracy and velocity from a gas operated
repeating firearm as that of a bolt action firearm. The system of
the present invention further helps reduce the amount of fouling of
the bolt as occurs in other gas operated firearms.
[0009] The structure of the preferred embodiment of the device of
the present invention broadly comprises the following: a barrel
side end cap; a target side end cap; a plenum tube or cylinder; at
least one chamber wall; and a gas tube hole connected to a return
gas tube. The barrel side end cap is designed to be affixed to the
end of a rifled gun barrel. The device may be affixed to the barrel
by any method, not limited to the following: threaded, welded,
bolted, snap-on, quick attach, clamp etc. The barrel side end cap
may be fabricated from, but not limited to, steel, stainless steel,
titanium, aluminum, polymer, ceramic, Inconel, etc. The barrel side
end cap also allows for the bullet to pass through without contact
and thereafter enter into the buffer plenum enclosure. The barrel
side end cap preferably has a hole in the center with a diameter
that allows for connection to the barrel and for the bullet to pass
through without contact.
[0010] The target side end cap of the present invention is designed
to allow the bullet to leave the buffer plenum and retain as much
gas as possible in the plenum enclosure without contacting the
bullet. The diameter of the central hole in the target side end cap
should be as close to the bullet diameter as possible without
allowing contact with the bullet as it passes through. This ensures
as much gas pressure as possible is retained in the plenum for as
long as possible. Avoiding contact with the bullet ensures maximum
accuracy. The target side end cap may be attached to the rest of
the plenum assembly by any method, not limited to the following:
threaded, welded, bolted, snap-on, quick attach, clamp etc. The
target side end cap may be fabricated from, but not limited to,
steel, stainless steel, titanium, aluminum, polymer, ceramic,
Inconel, etc.
[0011] The plenum tube of the present invention connects and aligns
the barrel side end cap with the target side end cap. The plenum
tube or cylinder wall is designed to keep the barrel side end cap
concentric with the target side end cap. This ensures that the
projectile holes are perfectly aligned with the barrel so that the
bullet does not impact the plenum. The plenum tube also holds in
position the one or more chamber walls. The plenum tube may be
attached to the rest of the plenum assembly by any method, not
limited to the following: threaded, welded, bolted, snap-on, quick
attach, clamp etc. The plenum tube may be fabricated from, but not
limited to steel, stainless steel, titanium, aluminum, polymer,
ceramic, Inconel, etc.
[0012] The one or more chamber walls create multiple small chambers
inside the buffer plenum. The chamber walls are designed to fit
concentrically inside the plenum tube. The chamber walls each also
have a center hole designed to be just slightly larger than the
bullet diameter. The bullet should pass through this hole without
making contact. The preferred embodiment of the present invention
consists of multiple chamber walls. Creating multiple chambers
allows the buffer plenum to act as a capacitor and store the gas
charge to create continuous effective bolt pressure. The chamber
walls may be attached to the rest of the plenum assembly by any
method, not limited to the following: pressure fit, threaded,
welded, bolted, snap-on, quick attach, clamp etc. The chamber walls
may be fabricated from, but not limited to, steel, stainless steel,
titanium, aluminum, polymer, ceramic, Inconel, etc.
[0013] A gas tube hole is configured in the barrel side end cap.
This gas tube hole receives, retains, and supports the gas tube. As
the bullet enters the buffer plenum, the gas pressure in the plenum
escapes through the gas tube hole and into the gas tube where it
passes on to the bolt mechanism and cycles the firearm. The gas
tube hole may alternately be connected to a piston system for a
hard linkage to the bolt. The gas tube hole may be produced by, but
not limited to drilling.
[0014] The gas buffer plenum may, in an alternate embodiment, be
formed from the barrel stock. A suitable barrel could be counter
bored to form the plenum tube and thereby eliminate the barrel side
end cap. The plenum tube is preferably connected to the barrel side
end cap in one of the following ways, but not limited to: threaded
on, pressure fit, clamped, bolted, welded, quick attach, snap on,
etc. This interface must be precise so that the plenum tube and the
barrel side end cap maintain concentricity. The barrel side end cap
and the plenum tube may also be formed from the same piece of
material and made monolithic.
[0015] The chamber walls should be precisely held inside the plenum
tube. They must be held so that they maintain concentricity between
each other, the plenum tube, and the barrel side end cap. The
number of chamber walls, and the size of the chambers will vary on
caliber of the firearm and the optimization of the bolt cycling
mechanism. The buffer plenum may preferably be constructed of one
or more chambers. The chamber walls may be secured inside the
plenum tube in the following ways, but not limited to: threaded on,
pressure fit, clamped, bolted, welded, quick attach, snap on,
etc.
[0016] The target side end cap is preferably connected to the
plenum tube in the following ways, but not limited to: threaded on,
pressure fit, clamped, bolted, welded, quick attach, snap on, etc.
The plenum tube and the target side end cap may alternately be
formed from one piece of material. The target side end cap must
also be held in concentricity with the plenum tube. The center hole
of the target side end cap must be sized to allow the bullet to
pass through without contact, but with extremely tight clearance to
catch as much gas as possible. The gas tube hole should be aligned
with the gas tube of the firearm. Typically, this is vertically
aligned, but this does not have to be the case. However, the gas
tube hole must be aligned with the gas tube or the piston drive
system so as to provide adequate gas flow back to the bolt for
proper cycling.
[0017] In summary, the present invention provides a gas buffer
plenum positioned at the end of the barrel of an automatic firearm.
The barrel side end cap connects the system to the barrel. The
plenum tube holds the chamber walls and retains the gas pressure.
The target side end cap creates the final pressure chamber
enclosure and is attached to the plenum tube to lock the system
together. This gas buffer plenum allows the bullet to leave the
barrel of the firearm before the bolt of the firearm starts to
open. As the gas buffer plenum is filled with the exploding gas
behind the bullet, the gas chambers build and maintain pressure
that is then forced back through a hole in the plenum. The gas is
forced down a gas tube or into a piston system. Depending on the
configuration of the firearm, either the gas force, or the piston
strikes the bolt and cycles the firearm. The gas buffer plenum may
operate in semi-automatic or fully automatic function. The system
may also be used to retrofit a gas operated firearm that uses a
traditional gas block design.
[0018] The components of the system of the present invention could
be reconfigured by changing the number of chamber walls in the
assembly, and thus the length of the plenum tube. The plenum tube
may also be eliminated and the chamber walls may be fixed together
in series by welding, bolting or threading so that they generate
the same concentric line of chambers required for operation. The
gas tube hole may be positioned in any chamber space from any
direction. Repositioning of the gas tube hole to an alternate end
cap or plenum tube location can change the aesthetics and the
performance of the bolt cycling function. The components may also
interface with a gas tube back to the bolt, or reconfigured with a
piston shaft that contacts the bolt. The barrel of the firearm may
itself be machined to eliminate the need for a barrel side end cap,
with the plenum tube being formed as part of the barrel. The barrel
could also have a gas tube gun drilled into it to transmit the gas
back from the plenum tube.
[0019] The gas buffer plenum is preferably either installed on a
new gas operated firearm or retrofitted to an existing gas operated
firearm. The user aims this firearm at a target, removes the
firearm safety, and pulls the trigger to fire. As the round fires,
the exploding gas pressure forces the bullet down the barrel. As it
exists the rifling, it enters into the gas buffer plenum. The gas
pressure behind the bullet is transmitted into the chambers and
forced back through the gas tube hole. The gas travels from the gas
tube hole into the gas tube and back to the bolt in the receiver.
The gas pressure forces the bolt open, but not until after the
bullet has left contact with the barrel rifling. The bullet leaves
the gas buffer plenum and precisely impacts the target. The user
then depresses the trigger again to fire another shot, or may put
the firearm back on safety and cease fire. In fully-automatic mode,
the user could hold down the trigger and the firearm would continue
to load and fire rounds automatically.
[0020] The end of barrel gas plenum of the present invention can
not only be used as the gas operation system for a new firearm, it
may also be used as a retrofit kit for existing firearms. The port
hole of the barrel of an existing firearm can be plugged and the
gas block removed. Alternately, the gas block may be turned so that
it blocks the port hole in the barrel. Thereafter, the plenum of
the present invention may be added to the end of the barrel. A
longer gas tube may be connected between the receiver and the end
of barrel gas plenum. Alternately, a piston system may be installed
as the gas force transmission system.
[0021] The end of barrel gas buffer plenum may also be modified
with additional baffles and materials to form an integrated
suppressor. This would dramatically reduce the sound of the shot,
and still function to cycle the firearm.
[0022] Any gas operated firearm could benefit from the present
invention. The end of barrel gas buffer plenum may be designed onto
the end of the barrel of any new firearm, and connected to the
receiver with the standard gas tube or piston. Alternately, the
plenum may be retrofitted to any existing gas operated firearm. The
system would benefit by increased accuracy, cleaner operation and
more robust cycling of the firearm.
BRIEF DESCRIPTION OF THE DRAWINGS
[0023] FIG. 1 is a perspective view of a first preferred
implementation of the system of the present invention on a typical
firearm barrel removed from the associated firearm for clarity.
[0024] FIGS. 2A & 2B are perspective views of a second
preferred implementation of the system of the present invention
operable in association with a gas block valve positioned on the
barrel.
[0025] FIG. 3 is an exploded perspective view of the end of barrel
gas buffer plenum of the present invention.
[0026] FIG. 4 is an exploded side view of the end of barrel gas
buffer plenum of the present invention as shown in FIG. 3 and
positioned adjacent the end of the barrel of the firearm.
[0027] FIG. 5A is an assembled perspective view of the end of
barrel gas buffer plenum of the present invention showing the
internal positioning of the various components of the plenum.
[0028] FIG. 5B is a cross-sectional side view of the end of barrel
gas buffer plenum of the present invention showing the internal
structures of the various components of the plenum.
[0029] FIGS. 6A & 6B are perspective views of the end of barrel
gas buffer plenum of the present invention showing the barrel side
(FIG. 6A) and the target side (FIG. 6B).
[0030] FIGS. 7A & 7B are perspective views of the barrel side
end cap of the end of barrel gas buffer plenum of the present
invention showing the external face (FIG. 7A) and the internal face
(FIG. 7B).
[0031] FIGS. 8A & 8B are perspective views of a typical (one of
three in the preferred embodiment) chamber wall of the end of
barrel gas buffer plenum of the present invention showing the
barrel side face (FIG. 8A) and the target side face (FIG. 8B).
[0032] FIGS. 9A & 9B are perspective views of the target side
end cap of the end of barrel gas buffer plenum of the present
invention showing the internal face (FIG. 9A) and the external face
(FIG. 9B).
[0033] FIG. 10A is a detailed perspective view of the barrel
mounted gas block valve of the system of the present invention.
[0034] FIG. 10B is a detailed side view of the top component of the
barrel mounted gas block valve of the system of the present
invention.
[0035] FIGS. 10C & 10D are detailed side views of the rotating
valve core of the barrel mounted gas block valve of the system of
the present invention; the view in FIG. 10D rotated 90.degree. from
the view in FIG. 10C.
[0036] FIG. 10E is a detailed perspective view of the valve lever
of the barrel mounted gas block valve of the system of the present
invention.
[0037] FIG. 10F is a detailed perspective view of the bottom
component of the barrel mounted gas block valve of the system of
the present invention.
[0038] FIGS. 11A & 11B are detailed side elevational views of
the barrel mounted gas block valve of the system of the present
invention; FIG. 11A showing the valve in a condition for directing
gas up through the prior art barrel port back to the bolt action,
and FIG. 11B showing the valve in a condition for directing gas
from the end of the barrel plenum of the present invention back to
the bolt action.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] Reference is made first to FIG. 1 which is a perspective
view of a first preferred embodiment of the system of the present
invention implemented on the end of a typical firearm barrel,
removed from the associated firearm for clarity. Gas cycling system
10 in the first preferred embodiment includes end of barrel gas
buffer plenum 12 positioned on the end of firearm barrel 15 and
connected to the weapon receiver by way of gas tube 19. Gas buffer
plenum 12 is shown to generally comprise plenum tube 22 with target
side end cap 32. Centered in end cap 32 is hexagonal shaped exit
port 24 suitable for facilitating the rotation of gas buffer plenum
12 onto the threaded end of a typical firearm barrel. Gas tube 19
shown in FIG. 1 extends from a return port (not seen in this view)
positioned on the barrel side of gas buffer plenum 12 and directs
the collected pressurized gas from the gas buffer plenum 12 to
conduct it back to the receiver of the weapon, whereby the high
pressure gas may serve to automatically activate the bolt of the
firearm.
[0040] Reference is next made to FIGS. 2A and 2B which are
perspective views of a second preferred embodiment of the system of
the present invention implemented on a typical firearm barrel
having an existing barrel gas port. Gas buffer plenum 12 is the
same in this second embodiment and forms the primary component of
the system of the present invention. In addition to gas buffer
plenum 12, however, gas block valve 14 is positioned over an
existing or drilled gas port in barrel 16. Gas tube 18 carries high
pressure gas back from gas port valve 14 to the receiver of the
weapon. Gas tube 20 connects the gas buffer plenum 12 with the gas
port valve 14. Operation of gas port valve 14 by way of its
attachment to barrel 16, using base half component 26, is achieved
by movement of valve lever 28 in a manner described in more detail
below. FIG. 2A shows a target side perspective view of the system
with target side end cap 32 and exit port 24. FIG. 2B provides a
barrel side perspective view of the second preferred embodiment of
the system of the present invention showing all of the same
components as FIG. 2A but additionally showing barrel side end cap
34 and hexagonal shaped barrel attachment fitting 30.
[0041] FIG. 3 is an exploded perspective view of the end of barrel
gas buffer plenum 12 of the present invention. In this view, gas
buffer plenum 12 is shown to be assembled along a single axis of
each of the generally cylindrical or disc shaped components of the
plenum. The view in FIG. 3 is from the target side of the plenum
and includes target side end cap 32 with exit port 24. Providing
the enclosing wall for the plenum is plenum tube 22 which is a
simple cylindrical wall with appropriately positioned end fittings
to receive target side end cap 32 and barrel side end cap 34.
[0042] Positioned within plenum tube 22, between target side end
cap 32 and barrel side end cap 34, are one or more chamber walls
36a-36c. Depending upon the particular firearm to which the gas
plenum is to be attached, the number of chamber walls 36 may vary
from one to three or more. The greater number of chamber walls
increases the collected high pressure gas that is returned to
effect the bolt action on the weapon that is desired. The preferred
embodiment of the present invention shown in FIG. 3 includes three
such chamber walls, 36a, 36b, and 36c.
[0043] FIG. 4 is an exploded side view of the end of barrel gas
buffer plenum of the present invention shown in FIG. 3 and
positioned as it would be adjacent the end of the barrel of the
firearm. In the view of FIG. 4, barrel 16 is shown positioned
parallel to gas tube 20 where they would be connected to barrel
side end cap 34 by way of barrel attachment fitting 30. One or more
chamber wall components 36a-36c are shown positioned between barrel
side end cap 34 and target side end cap 32. Surrounding the three
chamber walls 36a-36c, and sized with fittings appropriate for
receiving end caps 32 and 34, is plenum tube 22. The manner in
which each of these components is assembled to form the closed gas
buffer plenum is described in more detail above.
[0044] FIGS. 5A & 5B, as well as 6A & 6B, show the fully
assemble gas buffer plenum of the present invention. FIG. 5A is a
perspective view of gas buffer plenum 12 shown fully assembled with
each of the internal components visible as they would be positioned
and oriented for operation of the gas buffer plenum. FIG. 5A is an
assembled perspective view of the barrel gas buffer plenum 12 of
the present invention showing the internal positioning of the
various components of the plenum. In this view plenum 22 is shown
to surround the various chamber walls as described above, and to be
closed off on the target side with target side end cap 32
positioning exit port 24 with projectile aperture 42. On the
opposite side of gas buffer plenum 12 is barrel side end cap 34
with barrel attachment fixture 30 providing inlet opening 38,
typically internally threaded to receive the external threading of
the barrel to which the gas buffer plenum is attached. Gas return
port 40 is also shown in dashed outline form in FIG. 5A whereby
collected high pressure gas is ducted back to the firearm by way of
the connecting gas tube (not shown).
[0045] FIG. 5B is a cross-sectional view taken through the center
line of gas buffer plenum 12 of the present invention. In this
view, each of the components is shown in cross-section starting
with the target side end cap 32 which fits securely into plenum
tube 22 and closes off the internal volume taken up generally by
chamber walls 36a-36c. The opposite end of plenum tube 22 is closed
off with barrel side end cap 34 which likewise fits tightly into
plenum tube 22 to fully enclose the gas buffer plenum with the
exception of the projectile path (dotted line arrow) and the return
gas path (solid line arrow).
[0046] Because the gas behind the projectile is rapidly expanding,
the passage of the projectile from the end of the firearm barrel
allows the expanding gas to be directed outward from behind the
projectile rather than simply pushing the projectile forward, as it
does within the barrel. This outward expansion of the gas is
captured and directed by each of the chamber walls 36a-36c. The
greater the number of chamber walls, the more of the high pressure
expanding gas is collected and eventually ducted back to the weapon
receiver through gas return port 40 by way of the gas tube (not
shown). Each of the components of the gas buffer plenum 12 shown in
FIGS. 5A & 5B, may be assembled through a variety of secure
fittings and seam closures as described above. Again, other than
the intended projectile ports and gas return port, all seams for
gas buffer plenum 12 should be closed so as to fully contain and
appropriately direct the high pressure gas that the plenum
experiences. Again, various methods of assembling and securing the
components together with tight seams are anticipated. Those skilled
in the art will recognize that the basic structures of the gas
buffer plenum shown in FIG. 5B (for example) may be constructed
from separate components, or may be machined from a single solid
material component, or as few as two attached milled and machined
components. The various components described in the preferred
embodiment herein need not be configured separately, but do
describe as separate components, the various essential features of
the fully assembled or fully constructed gas buffer plenum 12.
[0047] FIGS. 6A & 6B are perspective views of the end of barrel
gas buffer plenum 12 of the present invention showing the barrel
side (FIG. 6A) and the target side (FIG. 6B). On the barrel side
shown in FIG. 6A, plenum tube 22 is shown to be closed off with
target side end cap 32 and barrel side end cap 34. Positioned on
barrel side end cap 34 is barrel attachment fitting 30 with barrel
connection port 38. Also shown on barrel side end cap 34 is gas
return port 40. FIG. 6B shows the target side of gas buffer plenum
12, providing plenum tube 22 closed off with target side end cap 34
and barrel side end cap 32. Positioned on barrel side end cap 32 is
hexagonal exit port fitting 24 with projectile aperture 42 shown
centered in the construction.
[0048] FIGS. 7A & 7B are perspective views of the barrel side
end cap of the end of barrel gas buffer plenum 12 of the present
invention, showing the external face (FIG. 7A) and the internal
face (FIG. 7B) of the component. The barrel side end cap, in the
preferred embodiment, is constructed from a generally cylindrical
wall 48 sized to fit within a machined recess in plenum tube 22 as
described above. Cylindrical wall 48 is closed by way of circular
wall 46 which establishes barrel side face 44. Centrally positioned
within barrel side face 44 is barrel attachment fitting 30 with
barrel attachment port 38. Also positioned within barrel side face
44 is gas return port 40 to which gas tube (not shown) is attached.
FIG. 7B shows the internal features of barrel side end cap 34 with
cylindrical wall 48 closed by wall 46 with the central port 38 and
gas return port 40 shown positioned therein.
[0049] FIGS. 8A & 8B are perspective views of a typical (one of
three in the preferred embodiment) chamber wall of the end of gas
barrel buffer plenum of the present invention showing the barrel
side face (FIG. 8A) and the target side face (FIG. 8B). The
construction of chamber wall 36 includes cylindrical wall 54 with
internal circular wall 56. Centrally positioned on circular wall 56
is gas extraction dome 52 which is a portion of the interior
chamber wall that extends towards the barrel and generally serves
to spread the expanding gas out to all sides after the passage of
the projectile through projectile port 50. In this manner, the
expanding gas directed to the side, may return by way of the gas
return port (not shown), having been collected by the one or more
chamber walls as the projectile passes through the gas buffer
plenum and the expanding gas is directed outward by the shaped
configuration of each of the chamber walls.
[0050] FIGS. 9A & 9B are perspective views of the target side
end cap of the end of barrel gas buffer plenum of the present
invention showing the internal face (FIG. 9A) and the external face
(FIG. 9B). Like barrel side end cap 34, target side end cap 32 is
constructed of cylindrical wall 58 closed off with circular wall 60
through which projectile port 42 is centrally configured. Circular
edge 62 provides the seat against which plenum tube 22 fits in
order to fully close off the gas buffer plenum. FIG. 9A shows the
target side view of the target side end cap, again disclosing
cylindrical wall 58 which fits within plenum tube 22 as well as
edge 62 which meets the mating edge of plenum tube 22. Target side
face 60 is shown to centrally contain exit port 24 with projectile
exit aperture 42 centrally positioned therein.
[0051] Reference is next made to FIGS. 10A-10F for a detailed
description of an optional barrel mounted gas block valve to
complete certain embodiments of the system of the present
invention. Whereas the end of barrel gas buffer plenum 12 that is
the primary focus of the present invention may be utilized in
conjunction with firearms that do not have existing barrel gas port
return structures, it is also possible to retrofit an existing
automatic firearm that does incorporate a barrel gas port so that
it may utilize the buffer plenum of the present invention in a
replacement or an alternate manner. The gas block valve 14 shown
initially in FIGS. 2A & 2B, may be positioned on the barrel of
the firearm in place of whatever existing return gas port
connection may already be in place. The structure of gas block
valve 14 when it is used in an alternate preferred embodiment of
the present invention is as shown in FIGS. 10A-10F.
[0052] FIG. 10A is a detailed perspective view of the barrel
mounted gas block valve of the second preferred embodiment of the
system of the present invention. In this view, gas block valve 14
is configured as it would appear mounted to the barrel of the
firearm. The barrel itself is removed in this view for clarity, but
would be positioned through barrel port 68 configured by the
connection of the two halves of gas block valve 14. A top half 64
is positioned on the top of the barrel, while a bottom half 26 is
aligned and connected to the top half through a number of
attachment bolts, screws, or the like. The four attachment bolts or
screws may be positioned in apertures 66 on the top half 64 of the
valve, and may be received into threaded apertures 94 which are
positioned in an aligned manner on the bottom half 26 of the gas
block valve.
[0053] The object of gas block valve 14 is to allow the user to
direct the expanding gases within the barrel back to the firearm
receiver, either in the conventional manner by ducting them away
from a position on the barrel where a gas port has been drilled, or
closing the gas port on the barrel and conducting the expanding gas
back from the end of barrel gas buffer plenum of the present
invention. In FIG. 10A, forward port 70 in the top half 64 of gas
block valve 14 receives the expanding gas from the end of barrel
gas buffer plenum of the present invention. Valve lever 28 allows
the user to switch between the gas port drilled in the barrel and
the gas port 70 receiving the expanding gas from the end of barrel
gas buffer plenum. Valve lever 28 moves within slot 74 positioned
on the side of top half 64 of gas block valve 14. Gas port 72
directs the expanding gas from either of the two selected sources
back to the receiver of the firearm.
[0054] FIGS. 10C & 10D show in detail the structure of the
internal core of gas block valve 14, comprising a rotating cylinder
with appropriately constructed conduits to alternately direct
expanding gas straight through the valve from the gas buffer
plenum, or up from the gas port in the barrel and out the back of
the gas block valve. Rotating valve core 76 pivots on axis 82 and
is moved by the use of valve lever 28, which is positioned within
captive slot 80 on the side of the rotating core. Port 88 connects
straight through the core to port 86 and connects the gas input
from the gas buffer plenum to the gas output on the valve when the
gas port in the barrel is cut off. Rotating the valve core 76
positions gas port 85 in the core with the gas port drilled in the
barrel (see FIG. 11A) and conducts the expanding gas therefrom out
through gas port 84 in valve core 76 at a right angle to the gas
port drilled in the barrel. Dashed line arrows in FIGS. 10C &
10D represent the two alternate flows of expanding gas through
valve core 76.
[0055] FIG. 10E is a detailed perspective view of valve lever 28
comprising captive slot tab 92 structured to engage and be held
captive by slot 80 in the rotating core, as well as lever handle
90. FIG. 10F is a detailed perspective view of the bottom half 26
of gas block valve 14 which attaches to top half 64 in the manner
described above.
[0056] FIGS. 11A & 11B show in greater detail the manner in
which the various gas flow conduits are alternately established
depending upon the rotation of valve lever 28 and its corresponding
rotation of valve core 76. FIG. 11A shows a manner of utilizing the
gas port drilled or pre-drilled into the barrel of the firearm
comprising barrel gas port 96. Port 96 represents a drilled passage
from the external surface of the barrel to the rifled bore 100 of
the barrel 16. In the view of FIG. 11A, port 70 connects by way of
gas tube 20 forward to the gas buffer plenum of the present
invention. Port 72 connects the gas block valve 14 by way of gas
tube 18 to the receiver mechanism for the firearm.
[0057] FIG. 11B shows the result of rotating valve core 76 by
pushing valve lever 28 forward, thereby cutting off barrel port 96
and opening the straight through conduit of valve core 76,
comprising connecting port 88 with port 70 and port 86 with port
72. This straight through configuration shown in FIG. 11B
represents the preferred use of the system of the present
invention, cutting off any pre-existing barrel gas ports and
utilizing the end of the barrel gas buffer plenum. In FIGS. 11A
& 11B, gas flow is shown with solid line arrows, and the path
of the projectile through the barrel is shown with dotted line
arrows.
[0058] While the present invention has been described in
conjunction with a number of preferred embodiments, those skilled
in the art will recognize that certain modifications to the
described embodiments still fall within the spirit and scope of the
invention. In particular, the number of chamber walls used to
construct the gas buffer plenum of the present invention will vary
depending upon the caliber of the projectile and its gunpowder
load. In general, the more chamber walls that are positioned within
the gas buffer plenum, the greater quantity of high pressure gas is
directed backward to the receiver of the firearm to activate the
bolt mechanism. Different bolt mechanisms require varying levels of
force to properly activate and any required force can be generated
by selecting the size and number of the chamber walls within the
gas buffer plenum. In addition, although a gas block valve has been
described in connection with the present invention, it is also
possible to simply close off an existing gas port in the barrel of
a firearm and utilize instead only the gas buffer plenum of the
present invention. Various mechanisms for closing off pre-drilled
gas ports in barrels are anticipated.
[0059] The overall geometry of the gas buffer plenum described
herein may also vary depending upon the particular firearm to which
the device is attached. Those skilled in the art will recognize
that there are limitations on the overall diameter of the preferred
embodiment for the gas buffer plenum that are dictated by the
ability to maintain target sighting across the plenum when attached
to the end of the barrel. Otherwise, the diameter of the gas buffer
plenum is variable and may be adjusted both according to the number
of chamber walls to be positioned within the plenum and the overall
force required to activate the bolt of the automatic weapon. These
variations in geometry, while still utilizing the basic structures
of the present invention, do not necessarily depart from the scope
of the invention as defined by the claims which follow.
* * * * *