U.S. patent number 3,742,638 [Application Number 05/055,838] was granted by the patent office on 1973-07-03 for bolt action assembly.
Invention is credited to James M. Archer.
United States Patent |
3,742,638 |
Archer |
July 3, 1973 |
BOLT ACTION ASSEMBLY
Abstract
A bolt action assembly for firearms comprising a bolt slidably
mounted in an action frame bore. The bolt is closed and
substantially solid in cross section at its rearward end and is
fitted with a removable bolt head at its forward end. The bolt
rides in a ball bearing bushing suitably positioned in the action
frame bore. Extractors are provided on the bolt head for gripping a
cartridge rim and are opened through the force or reaction between
the extractors and the cartridge rim. Enlarged diameter portions in
the action frame bore permit the extractor to open to grip the
cartridge rim in the chambering phase and to release the cartridge
casing in the ejection phase. The internal surfaces of the bore
other than at the enlarged portions normally maintain the
extractors in the closed position. The bolt head has locking lugs
thereon which cooperate with lugs on a recoil ring to maintain the
bolt in the closed position. The recoil ring and bolt head are
removable to allow substitution of another bolt head and recoil
ring accommodating a cartridge of a different caliber.
Inventors: |
Archer; James M. (Billings,
MT) |
Family
ID: |
22000480 |
Appl.
No.: |
05/055,838 |
Filed: |
July 17, 1970 |
Current U.S.
Class: |
42/25; 42/16 |
Current CPC
Class: |
F41A
15/12 (20130101); F41A 3/30 (20130101); F41A
3/64 (20130101) |
Current International
Class: |
F41A
15/00 (20060101); F41A 3/64 (20060101); F41A
15/12 (20060101); F41A 3/30 (20060101); F41A
3/00 (20060101); F41c 015/00 (); F41c 011/00 () |
Field of
Search: |
;42/16,25 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Borchelt; Benjamin A.
Assistant Examiner: Jordan; C. T.
Claims
I claim:
1. A bolt action assembly for firearms for loading and extracting a
cartridge case comprising
a bolt action frame mounted on said firearm having a longitudinal
bore therein for receiving a cartridge case having an extractor
groove and rim,
a bolt slidably mounted in said bore having a head and a body
portion and a substantially flat front face on said head
portion,
extractors pivotally mounted for movement between an opened and
closed position on said bolt head for engagement with a cartridge
rim one of said extractors has a pivot point closer to the
center-line of said bolt body than the pivot points of the other
extractors, and
cam surfaces on said extractors,
said bore having an enlarged diameter portion permitting said
extractors to pivot radially outwardly upon reaction of the
engagement of said cartridge rim and said cam surfaces when said
bolt moves against said cartridge case whereby said cartridge rim
moves past said extractors and abuts said face, and
means in said bore for closing said extractors about said case rim
upon continued movement of said bolt and said case.
2. A bolt action assembly as defined in claim 1 and wherein said
bolt head is removably attached to said body portion at one end
thereof and the other end of said bolt body portion is closed and
substantially solid in cross-section.
3. A bolt action assembly as defined in claim 1 and including a
removable recoil ring in the forward end of said bore and locking
lugs on said bolt head portion for cooperating with said recoil
ring for locking said bolt in closed position.
4. A bolt action assembly as defined in claim 1 and wherein
anti-friction bearing means are provided in said bore engaging said
bolt for facilitating the sliding movement of said bolt within said
bore.
5. The bolt action assembly as defined in Claim 1 and including a
second enlarged diameter portion in said bore for permitting said
extractors to pivot outwardly to the open position to release said
cartridge case near the point of the rearmost travel of said bolt
and ejector means for ejecting said cartridge.
6. A bolt action assembly as defined in Claim 5 wherein one of said
extractors is normally spring biased to the closed position and
said ejector means cooperates with said spring-biased extractor
which serves as a fulcrumpoint to eject said cartridge when said
extractors are adjacent said second enlarged diameter portion.
7. A bolt action assembly as defined in Claim 1 and including a
recoil ring having a front side and a rear side in said bore and
aligned therewith at the forward end of said bore, said rear side
of said recoil ring being adjacent said enlargement, second cam
surfaces defined by tapered raceways through said ring,
recoil lugs on the front side of said ring and extending
therethrough,
locking lugs on said bolt head portion,
said bolt head extending through said recoil ring and said locking
lugs extending through said raceways and cooperating with said
recoil lugs to lock said bolt in the closed position.
8. A bolt action assembly as defined in claim 7 and including
tapered ramps extending from said recoil lugs and rearwardly of
said ring, whereby said cartridge engages said ramps which guides
said cartridge into said ring.
9. A bolt action assembly as defined in claim 4 and wherein said
anti-friction bearing means comprises a recirculating ball
bushing.
10. A bolt action assembly for a firearm having a removable barrel
comprising a bolt action frame mounted on said firearm having a
longitudinal bore therein in communication with said barrel at one
end thereof and receiving a cartridge of a certain caliber,
a recoil ring mounted on said action frame in said bore end
adjacent said barrel and aligned therewith,
a bolt slidably received in said bore having a body portion and a
head portion rotatable relative to said recoil ring,
locking lugs on said bolt head portion cooperating with said recoil
ring to lock said bolt in closed position,
said bolt head portion being removable from said bolt body and said
recoil ring being removable from said bore for purposes of
substituting a bolt head portion and a recoil ring accommodating a
cartridge of a different caliber.
11. A bolt action assembly as defined in claim 10 and including
extractors pivotally mounted on said locking lugs.
12. In a bolt action assembly for a firearm comprising
a bolt action frame on said firearm having a longitudinal bore
therein for receiving a cartridge casing having an extractor groove
and rim,
a bolt slidably received in said bore having a body portion, a
detachable head portion and a substantially flat front face on said
head portion,
a handle on said bolt for moving said bolt within said bore,
ball bearing means within said bore and engaging said bolt to
enable substantially frictionless sliding movement,
extractors pivotally mounted on said head portion for engaging and
gripping a cartridge case rim, the diameter of said bore closely
approximating the outer diameter of said bolt head portion thereby
normally maintaining said extractors in closed position,
a recoil ring having a front and rear side at the forward end of
and aligned with said bore,
detent means in said ring for impeding the movement of a cartridge
case through said ring,
locking lugs on said bolt engaging said front side of the recoil
ring when said bolt is closed and rotated to a locked position,
cam surfaces on said extractors for engaging a cartridge case
rim,
a first enlargement in said bore adjacent the rear side of said
recoil ring whereby said extractor claws are permitted to pivot
outwardly upon reaction of the cartridge rim and said cam surfaces
when the movement of said cartridge relative to said bolt is
impeded by said detent means thereby permitting said cartridge rim
to move past said extractors and abut said bolt face,
tapered raceways in said ring for closing said extractors about
said case rim as the cartridge and bolt head pass through said
ring,
a second enlarged diameter portion in the rear of said bore
allowing the extractors to pivot outwardly and release said
cartridge case after retraction of the bolt,
one of said extractors normally being spring-biased to a closed
position with a deeper pivotal position, and
ejector means cooperating with said spring-biased extractor to
eject the cartridge case when extractors are adjacent said second
enlarged diameter portion.
Description
This invention relates to a bolt action assembly for a firearm. It
is an object of this invention to provide a bolt action assembly
for a firearm which overcomes numerous disadvantages of
"conventional" bolt action assemblies.
The structural components of a bolt action assembly, i.e., the bolt
and the recoil lugs must be of great strength in order to withstand
the tremendous rearwardly directed pressure exerted upon firing of
a cartridge.
It is desirable to form these parts of a high strength metal which
is quite expensive both to obtain and to machine to proper
dimensions. However, since the lugs are generally integral with the
bolt frame housing and the bolt is a unitary structure, the entire
housing and bolt must be formed of the high grade metal even though
the major portions thereof are not subjected to the high pressure.
This is quite expensive, consequently, a number of firearms are
manufactured with bolts and recoil lugs of less expensive and less
durable metals which not only increase the danger factor but also
shorten drastically the life of the bolt action assembly.
It is an object of this invention to overcome the aforementioned
disadvantages in conventional firearms by providing replaceable
component parts of a very high grade of steel. It is proposed to
provide a high-strength recoil ring having recoil lugs thereon,
which ring is removably positioned in the action frame bore.
Further, a bolt is provided having a detachable head portion which
is made of a high-strength metal. By using a replaceable recoil
ring and bolt head -- the component parts which absorb the most
force and therefore must be the strongest -- the remaining parts,
i.e., the main body portion of the bolt and the action frame
housing, may be of less expensive materials therefore maintaining
the economical practicability of the forearm while enhancing the
safety and durability factors. Further, by providing a recoil ring
and bolt head which may be replaced with another bolt head and
recoil ring, repair in case of damage is greatly facilitated. One
merely needs to remove the barrel and replace the recoil ring
without machining or replacing the entire action frame and to
remove the bolt and replace the bolt head without replacing the
entire bolt. In most conventional firearms, the recoil lugs, which
are part of the recoil ring of this invention, are integral
portions of the action frame housing and the bolt is an integral
one piece member.
A further and very important object of this invention is to provide
a replaceable recoil ring and bolt head which may be interchanged
with a recoil ring and bolt head of a different size to accommodate
cartridges of different calibers. The existing recoil ring of given
dimensions may be replaced with another ring either larger or
smaller in a dimension affecting the head space of the firearm.
Thus, the machine work necessary to adjust head space in a
conventional integral design may be avoided. Bolt head and recoil
ring assemblies may be offered to the consumer in kit form for use
with one or more different size cartridges in a particular firearm.
In this way, one firearm may fill the need wherein two or more were
required previously.
It is a further object of this invention to increase the safety
factor of a firearm by providing a bolt which is closed at its
rearward end and substantially solid in cross section. In
conventional designs, the firing pin and firing pin spring, etc. is
assembled from the rear of the bolt through suitable bores therein
by removing a bolt sleeve which normally is threaded in the end of
the bolt. The build up of escaped gases sometimes is sufficient to
"blow" the bolt sleeve causing injury to the user. By providing a
removable bolt head, the firing pin, ejector mechanism, etc., may
be inserted through the front of the bolt with the rearward end of
the bolt being substantially solid and, therefore, safe from
spontaneous disassembly due to the high pressure in the event gases
are loosed as when the cartridge case bursts or the primer is
pierced by the firing pin.
Further in reference to gas control, there exists an extremely
close fit between the bolt body and the action frame bore of this
invention. The bolt head is provided with locking lugs and
extractors. Just to the rear of the bolt head at the leading
portion of the bolt body is a substantially conical shoulder which
acts as an obstacle to loosed gases. The shoulder will deflect the
gases and slow them as they attempt to travel further down the
action frame bore. Positioned in the bore behind the shoulder are
annular, combination rubber and steel seals which encompass the
bolt periphery and work on a principle whereby the greater the
pressure the tighter the seal with the bolt body. In this manner,
the gases will be safely contained in front of the action until
they have dissipated into the atmosphere through the cartridge
ejection port. Those gases which enter the bolt body through the
firing pin hole would be contained by means of a rubber seal around
the firing pin until they too have been dissipated through suitable
gas ports in the body.
Another object of this invention is to provide a bolt which
reciprocates freely in the bolt action bore. In conventional
designs the bolt is characteristically loose and sloppy when it is
in the rearmost position. This condition causes the bolt to bind
when it is rapidly operated or when there is substantial side
pressure applied upon the closing of the bolt. This problem is
overcome by this invention by means of a recirculating ball bushing
which is positioned in an inset in the action bore and surrounds
the bolt body. The bushing engages the bolt body within rather
close tolerances precluding substantially all relative lateral
movement between the two members. Further, due to the
anti-frictional nature of the ball bushing there is almost no
frictional bolt drag. The ball bushing takes the major load during
operation.
Another important object of this invention is to provide an
extractor mechanism which embodies great strength and simplicity.
The bolt head is provided with extractors spaced around the
periphery of the bolt head which are pivotally mounted to swing
radially outwardly to an open position allowing the cartridge case
rim to slide past the extractors and to abut the bolt head face.
The extractors are normally maintained in the closed position
merely by the interior surfaces of the action frame bore. That is,
the action frame bore is of an inside diameter only slightly
greater than the outer diameter of the bolt head as defined in the
locking lug and prevents the pivoted extractor from swinging
radially outwardly to the open position. The front surface of each
extractor is provided with a cam surface which engages a cartridge
casing rim injected into the action frame bore. The bolt head
pushes the cartridge case into the recoil ring which is provided
with spring-loaded ball detents which impede the forward movement
of the cartridge case. Adjacent the recoil ring is an enlarged
diameter portion of the action frame bore which permits the
extractors to pivot radially outwardly. The extractors which are in
abutment with the cartridge case rim will pivot radially outwardly
at the enlarged portion due to the reaction of the cam surfaces
with the peripheral edge of the cartridge case rim. As the
extractors open, the cartridge case rim slides past the extractors
and abuts the bold head face. The recoil ring is provided with
tapered raceways. The raceways define a diameter approximating the
diameter of the enlarged portion on the rear side of the ring but
taper to define a diameter on the front side of the ring
approximating the diameter of the bore. The tapered raceways
receive the locking lugs and serve as cams for closing the
extractors around the cartridge case rim. Further forward movement
of the bolt head moves the locking lugs past the recoil ring and
partial rotation of the bolt by means of a bolt handle causes the
locking lugs to engage the recoil lugs on the forward side of the
recoil ring thereby locking the bolt in closed position. After
firing of the cartridge, the cartridge case is withdrawn by means
of the extractors gripping the cartridge case rim. At least one of
the extractors continues to grip the rim as the case is drawn back
through the enlarged area because the one extractor is provided
with spring biasing means normally keeping it closed and is pivoted
about a pivot pin which is mounted closer to the centerline of the
bolt body than the pins of the other extractors. The spring is of
only sufficient tension to safely withdraw the case from the detent
means and through the enlarged area after which the extractors are
once again limited in the swinging action because of the internal
surfaces of the action frame bore. A second enlarged area is
located in the action frame bore adjacent the extractor claws at
the rearmost travel of the bolt whereupon the extractors are again
allowed to open. An ejector mechanism pushes outwardly on the
cartridge case rim opposite the spring biased extractor. The
spring-biased extractor serves as a fulcrum causing the cartridge
case to pivot through the cartridge ejection opening in the action
frame.
A further object of this invention is to provide extractors of
relatively large proportions having the necessary inherent strength
and for engaging the cartridge case rim over a substantial portion
of its periphery up to 100 per cent. The extractors are
mechanically closed and maintained in a closed position in a manner
to preclude the extractors from springing or jumping over the
cartridge case rim under any circumstances.
Specifically this invention comprises a bolt action assembly for a
firearm comprising a bolt action frame having a longitudinal bore
therein for receiving a cartridge casing having an extractor groove
and a rim. A bolt is slidably received in said bore having a body
portion and a detachable head portion and a substantially flat
front face on the head portion. The bolt slides through and is
supported by a circulating ball bushing which is positioned in the
bore. A handle is provided on the bolt for moving the bolt within
the bore. A recoil ring having a front and rear side is positioned
at the forward end of the action frame bore and is aligned
therewith. Detent means are provided in the recoil ring for
impeding the movement of a cartridge case therethrough. The bolt
head is provided with locking lugs adapted for cooperation with
recoil lugs on the front side of the recoil ring for purposes of
locking the bolt in closed position. Cartridge extractors are
pivotally mounted on the locking lugs and swing radially outwardly
from the closed to the open position. The inner diameter of the
action frame bore closely approximates the outer diameter of said
bolt head portion and normally maintains the extractors in the
closed position. Each of the extractors is provided with a cam
surface on its front face for contacting a cartridge case rim. A
first enlarged diameter portion is provided in the bore adjacent
the rear side of the recoil ring whereby the extractors are
permitted to pivot outwardly upon reaction of the cartridge rim and
said cam surfaces when the movement of the cartridge relative to
the bolt is impeded by said detent means. The cartridge rim then
moves past said extractors and to abut said face. Raceways in the
recoil ring are tapered from the enlarged diameter portion down to
the normal bore diameter for purposes of closing the extractors
about the cartridge case rim as the bolt head and cartridge case
move through the recoil ring. A second enlarged diameter portion is
provided at the rear of the bore allowing the extractors to pivot
outwardly and release the cartridge case upon retraction of the
bolt. One of the extractors is normally closed by a spring-biasing
means and is pivoted about a point closer to the centerline of the
bolt body and serves as a fulcrum point in cooperation with an
ejector means for ejecting the cartridge casing. The ejector means
comes into operation simultaneously with the arrival of the
extractors at the second enlarged diameter portions.
Referring now to the figures:
FIG. 1 is a cross sectional side view of the bolt action assembly
of the invention showing the bolt in the retracted position;
FIG. 2 is a cross sectional side view similar to FIG. 1 showing the
bolt in the closed but not locked position;
FIG. 3 is a top cross sectional view taken along lines 3--3 of FIG.
2;
FIG. 4 is a cross sectional side view with a full bolt head showing
a spent cartridge as it is released by the extractor mechanism with
the bolt in the retracted position;
FIG. 5 is a cross sectional view with a full bolt head showing the
initial engagement of the bolt head and extractors with the
cartridge case;
FIG. 6 is a cross sectional side view with a full bolt head showing
the extractors in the open position allowing the cartridge case to
abut the bolt face prior to being fully gripped by the
extractors;
FIG. 7 is a cross sectional side view with a full bolt head showing
the extractors being forced to the closed position about the
cartridge rim prior to the cartridge being chambered;
FIG. 8 is a cross sectional side view with a full bolt head showing
the cartridge chambered and the bolt in the closed but not locked
position;
FIG. 9 is a cross sectional view of the recoil ring taken
substantially along lines 9--9 of FIG. 8;
FIG. 10 is a view similar to FIG. 9 showing the bolt in the locked
position;
FIG. 11 is a front view of the recoil ring alone showing tapered
channels and retarder means in phantom;
FIG. 12 is a side view of the recoil ring;
FIG. 13 is a rear view of the recoil ring;
FIG. 14 is a front view of the bolt head; and
FIG. 15 is a view of the opposite side of the bolt head showing the
extractor with the deep-set pivot point.
Referring now to FIG. 1, the bolt action assembly of this invention
is indicated generally by the numeral 10. The bolt action frame 12
has a longitudinal bore 14 therein for receiving a cartridge casing
C having an extractor groove or rim. Slidably received in the bore
14 is a bolt generally indicated by the numeral 16 comprising a
body portion 18 and a head portion 20. The bolt is further provided
with a handle 21 for purposes of reciprocating the bolt in the
conventional manner. A ball bearing assembly 22 comprising a
bushing having recirculating balls therein is positioned within the
action frame bore 14 in an annular inset 24. The action frame 12 is
segmented at 26 by suitable threads and may be separated for
purposes of inserting the ball bearing bushing. The bushing is
further provided with annular seals 28 comprised of metal and
resilient materials such as plastic or rubber for tightly engaging
the cylindrical surface of the bolt body 18 to prevent gases from
passing along the area between the action frame interior surfaces
and the cylindrical surface of the bolt body. The seals are of the
type that grip more tightly the greater the pressure that is
exerted against them.
The bolt body 18 though not fully shown is closed at its rearmost
end and is substantially solid in cross section at that point.
Therefore, unlike conventional bolts, the firing pin mechanism is
inserted through the forward end of the bolt body by removing the
head portion 20. The head portion 20 is secured to the bolt body 18
by means of locking pin 30 which engages a slot in the neck portion
32 which is inserted in a cylindrical recess 34 in the bolt body
18. The bolt body 18 has along one side thereof a longitudinal slot
36 which is parallel with the axis of the bolt. A suitable follower
lug mounted on the action frame rides in the slot to insure linear,
non-rotatable movement of the bolt within the bore 14. The slot
includes a transversely extending section at its rearward end which
permits the bolt to be rotated to the locked position. An ejector
pin 38 which is normally spring-biased to the recessed position
flush with the bolt face 40 by spring means 42 is provided in the
head portion 20 and terminates in a right angular projection 44
which projects into slot 36. The ejector pin is caused to
reciprocate and project outwardly from the bolt face 40 when the
bolt reaches its rearmost position. At that point the right angular
member 44 engages the follower lug, not shown, forcing the ejector
pin forward against the action of spring 42.
The bolt head is provided with four radially spaced locking lugs 46
best shown in FIG. 15. Pivotally mounted on the locking lugs are
four extractors 48a, 48b, 48c and 48d which are moved from an open
to a closed position to grip the rim of the cartridge case and are
held in the closed position by the close confines of the inner
surfaces of the action frame bore 14. The extractors are permitted
to swing to the open position to grip a cartridge case rim prior to
the case being chambered and to release the cartridge case for
ejection after firing by enlarged diameter portions 50 and 52
respectively of the bore 14.
A removable recoil ring 54, best seen in FIGS. 9 through 13, is
positioned in an annular inset portion 56 in the action frame 12
with the inner diameter of the recoil ring being dimensioned to
admit a cartridge of a specified caliber. Recoil rings of various
sizes along with bolt heads of various sizes may be substituted in
the action frame to accommodate different caliber cartridges by
removing the barrel 58 which is threaded into the action frame. The
recoil ring is provided with tapered raceways 60 as best shown in
FIGS. 3 and 6 through 8, which receive the locking lugs 46 of bolt
head 20 as the bolt is moved forward through the recoil ring. The
raceways terminating on the rear side of the ring define an
interrupted circle of a diameter the same as that of the enlarged
diameter portion 50, while on the front side, the channels define a
circle of a diameter the same as that of the bore 14. The ring is
provided with tapered ramps 62 which serve to guide the cartridge
into the ring. The ramps extend rearwardly of the lugs 74 which
extend through the ring and are circumferentially spaced by the
race-ways 60.
Spring loaded detent means are positioned to project radially
inwardly of the recoil ring 54 to define a circle of a diameter
less than the outer diameter of a cartridge for which the ring is
adapted. The detent means is comprised of springs 64 with ball
detents 66. It is to be understood that the openings through which
the balls project are of a diameter less than the diameter of the
balls to prevent the balls from passing completely through the
openings.
It is to be emphasized that the extractors are not opened by any
separate mechanical means. The opening is effected by reaction with
the cartridge case rim when permitted by action frame bore
enlargements. The closing of the extractors is effected by the
closely surrounding action frame bore 14.
The operation of the bolt action can best be understood with
reference to FIGS. 4 through 8. A cartridge C is injected into the
bore 14 from a suitable magazine. The bolt 16 is pushed forward and
the cartridge is in abutment with the extractors 48a, 48b, 48c and
48d at a point in the bore 14 intermediate the two enlarged
diameter portions 50 and 52. In this position, the extractors are
in the closed position and the tips of the extractors define an
opening of a diameter less than that of the rim of the cartridge
such that the cartridge is not permitted past the extractors. At
this point, the cartridge case rim will be against the cam surfaces
of the respective extractors.
As the casing is pushed through the recoil ring 54, the ball
detents 66 grip the cartridge case impeding its forward movement.
At this point, the extractors on the bolt head are adjacent the
enlarged diameter portion 50. Due to the force of the reaction and
the particular angle of the cam surface against the cartridge case
rim, the extractors are forced to pivot to the open position and
are allowed to do so by means of the enlarged diameter portion 50.
Upon the extractors reaching the open position, the cartridge case
rim slips past the extractor edges or tips and abuts the bolt face
40. Continued movement of the bolt 16 causes the extractors to move
to the closed position gripping the cartridge case rim. The
extractor claws are forced to close position by the tapered races
60 which serve as cam surfaces forcing the closing action. Upon
further movement of the bolt, the cartridge C is chambered and the
bolt is rotated to the locked position in the conventional manner.
That is, the bolt is rotated to cause engagement of the locking
lugs and the recoil lugs 74 on the recoil ring. Each of the lugs 46
are provided with cam surfaces 47 to facilitate the smooth
engagement of the lugs 46 with the lugs 74. The bolt as shown in
FIGS. 2 and 8 is in the closed position but not the locked position
for purposes of clarity. It is to be understood that the bolt will
be rotated 45.degree. from the position shown when in the locked
position.
After the cartridge has been fired, the bolt is unlocked and pulled
back through the recoil ring 54. The cartridge is not released as
it passes through the enlarged diameter portion 50 due to one of
the extractors 48a, being spring biased to the closed position.
Further the extractor 48a has a pivot point spaced closer to the
centerline of the bolt than the other pivot points for the other
extractors as best seen in FIG. 15. The bolt continues its rearward
movement and stops at a point where the extractors are adjacent the
enlarged diameter portion 52. Simultaneously, the right angular
projection 44 is pushed forward by means of a follower lug, not
shown, riding in groove 36 causing the ejector pin 38 to project
outwardly against the cartridge case forcing the extractors 48a-d
to the fully open position. The extractors are of course permitted
to open because of the enlarged diameter portion 52. The ejector
pin 38 is offset with relation to the centerline of the bolt and is
positioned opposite the spring-biased extractor 48a having the
deeper set pivot point. Consequently, the ejector pin 38 pushes on
one side of the cartridge case rim and the spring biased extractor
48a serves as a fulcrum thereby causing the cartridge case to pivot
outwardly and through an ejection port.
During the firing of the cartridge in event of bursting, the
rearward movement of escaped gases is impeded by the conical
shoulder 78 of the bolt head. The tolerance between the internal
surfaces of the bore 14 and the exterior surface of the bolt 16 is
quite close to preclude gases from passing farther. Additionally,
the seals 28 prevent rearward movement of the gases and force them
through the main ejection port in the action frame.
It is to be understood that the invention disclosed herein is not
limited to the particular number of extractors or lugs or to any
particular positioning of the extractors or lugs. The lugs may
range from two to four in number and the extractors from one to
four in number.
As mentioned earlier, the bolt action may be easily modified to
accommodate a different caliber cartridge by substituting a
different barrel 58, a recoil ring 54 and bolt head 20.
In a general manner, while there has been disclosed an effective
and efficient embodiment of the invention, it should be well
understood that the invention is not limited to such an embodiment
as there might be changes made in the arrangement, disposition, and
form of the parts without departing from the principle of the
present invention.
* * * * *