Ordnance – Cartridge feeding – Holders
Reexamination Certificate
2000-10-18
2003-01-07
Johnson, Stephen M. (Department: 3641)
Ordnance
Cartridge feeding
Holders
C089S033170
Reexamination Certificate
active
06502495
ABSTRACT:
BACKGROUND OF THE INVENTION
A. Field of the Invention
This invention relates generally to the field of firearms. More particularly, the invention relates to a rotary magazine for a firearm that contains a mechanism for holding the bolt of the firearm in an open position after the last cartridge in the firearm has been fired and the bolt has recoiled, thereby signaling to the user that the magazine is empty. The invention is applicable to bolt-action, manually operated firearms, semi-automatic firearms, and fully automatic firearms.
B. Description of Related Art
It is known in the art to provide a hold-open feature by which the bolt remains in an open position after the last shot in a magazine has been fired. The purpose of the hold-open feature is to alert the user of the need to re-load the weapon, and to avoid an unnecessary and annoying attempted firing of the weapon when in fact the magazine is empty. Representative patents describing hold-open features include Roemer, U.S. Pat. No. 2,321,045; Ruger et al., U.S. Pat. No. 3,846,928, Ruger, U.S. Pat. No. 4,438,678, Smith, U.S. Pat. No. 4,594,935 and Johnson, U.S. Pat. No. 2,341,869.
The Johnson rifle described in the '869 patent is a rotary magazine semi-automatic weapon which saw limited duty in WW II. The Johnson rifle is also described to some extent in the publication Firearms Assembly 1, The NRA Guidebook to Shoulder Arms, pp. 144-145, published in 1972 by the National Rifle Association. The rifle includes a hold-open feature, however the hold open feature is a rather complex arrangement of mechanical parts that involve both on the rifle body and the magazine. As such, the design is not one suited to wide applicability, or suited to the situation in which a magazine is modified to provide the hold open feature and no other modifications are needed to the rest of the firearm.
It is the belief of the present inventor that many, if not most, rotary magazines for semi-automatic firearms do not contain a hold-open feature. One of the most popular of such firearms is the Ruger® 10-22-caliber semi-automatic rifle. Adding a hold-open feature to those firearms with rotary magazines that presently do not have a hold open feature would certainly improve the performance and overall experience in using the firearm. However, the addition of a hold-open feature, in which no modifications are made to the rest of the firearm, is a difficult design in which there certainly is no obvious solution. To see why this is the case, the magazine of Ruger® 10-22-caliber semi-automatic rifle will be briefly described.
Referring now to
FIGS. 1-3
, the factory or stock rotary magazine
10
for a Ruger® 10-22 semi-automatic rifle is shown isolated from the rest of the firearm. In
FIG. 1
, the magazine is shown in a perspective view looking down on a feed insert
12
and the magazine housing
14
. The feed insert
12
is a metal piece that receives the cartridges when they are inserted into the magazine. The feed insert has a flat planar surface
15
that the bolt slides over when the firearm is fired. A rotor
16
is positioned inside the magazine housing. The rotor
16
has a series of projecting ridge elements circumferentialy spaced about the shaft of the rotor that accommodate or receive the individual cartridges when the cartridges are inserted into the feed insert. A biasing spring (not shown) tends to bias the rotor in a clockwise direction as viewed from the rear of the magazine to move the cartridges to a firing position at the top of the feed insert. When the user inserts the cartridges, the force accompanying insertion the cartridge into the feed insert
12
past overcomes the force of the biasing spring, allowing the rotor
16
to rotate in a counterclockwise direction and receive the individual cartridges between the ridge elements of the rotor. One of the projecting ridges is slightly larger than the rest and is used to move the last cartridge up into firing position; this ridge
18
is shown in
FIGS. 1 and 2
. The last cartridge is held up in position by the rearmost portion
18
A of the ridge
18
by a wedging action. This wedging action also prevents further rotor rotation until the cartridge is pushed forward or removed in the improved magazine of this invention.
The unaltered, factory stock magazine of
FIGS. 1-3
holds ten rounds of 0.22 caliber long rifle ammunition. Each of the ten rounds is stripped off the magazine
10
and pushed forward into the rifle chamber and fired until the magazine is empty. The force of the rotor's biasing spring keeps each cartridge in turn jammed up into the feed insert's feed lips
20
in position for firing. The tenth round (last cartridge) relies upon the rearmost portion
18
A of the top portion of the ridge
18
to position it between the feed lips
20
in position for firing.
After the last shot is fired, the rotor is stopped from further rotation by interference between the ridge
18
and the feed insert at the location
24
shown in
FIGS. 1 and 2
. No further rotation is possible due to this mechanical interference. The design of the factory magazine was to intentionally prevent any further rotation to allow ease of loading of the first cartridge, i.e., insure sufficient space between the top of the rotor and the side of the feed insert to allow the first cartridge to be inserted into the magazine.
The magazine of
FIGS. 1-3
has no features to hold the rifle bolt open after the last shot has been fired. It is an object of the invention to provide modifications to a rotary magazine of the general type shown in
FIG. 1
to provide such a hold-open feature. Another principal feature of this invention is that the hold open feature is completely provided by the magazine, and as such does not require any modifications whatsoever to the firearm per se.
SUMMARY OF THE INVENTION
A rotary magazine is provided for a firearm having a bolt that reciprocates between an open position and a closed, firing position, in which the magazine includes features to hold the bolt in an open position after the last shot has been fired. The hold open features are provided entirely in the magazine, and no modification is needed to the firearm. While the rotary magazine of the present invention is particularly suitable for a semi-automatic firearm, such as the Ruger® 10-22-caliber semi-automatic rifle and magazines of similar design, and while the following text and accompanying figures describe various embodiments of a rotary magazine for that rifle, it will be appreciated that the scope of the invention encompasses other types of firearms having rotary magazines.
The inventive rotary magazine with the hold-open feature includes a magazine housing adapted for containing a plurality of cartridges. A feed insert is carried by the housing and has a planar surface along which the bolt travels when reciprocating between the closed and open positions. A spring-loaded rotor is contained within the housing that has a shaft rotating about an axis. The rotor advances the cartridges one by one to a firing position in the feed insert.
A hold-open lever is positioned within the magazine adjacent to the planar surface of the feed insert. The hold-open lever has a first position in which the lever is in an aligned condition relative to the planar surface of the feed insert, and a second or deployed position in which the lever is in a non-aligned condition relative to the planar surface. In the second position, the lever blocks movement of the bolt from the open position to closed position, holding the bolt open.
The shaft of the rotor carries a trip mechanism. The trip mechanism is provided as a means for moving the lever from the first position to the deployed position after the last shot has been fired. In particular, when the last cartridge is fired and the bolt has recoiled to the rear of the magazine, the rotor is permitted to rotate an additional amount (typically between 10 and 15 degrees), and this additional rotation allows the trip mechanism to contact the hold-open lever and thereby actuate the hold-op
Johnson Stephen M.
McDonnell & Boehnen Hulbert & Berghoff
LandOfFree
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