Patent Description:
A need persists for convenient means of utilizing economical ammunition (e.g., 22LR rounds) with an AR-<NUM> or M16 upper receiver to simulate more costly. <NUM> or <NUM> ammunition. <CIT> and <CIT> disclose ammunition magazines.

The present disclosure provides ammunition magazines and hold-open bolt carriers for using low-cost (e.g., 22LR) ammunition in a standard AR-<NUM> or M16 upper receiver. The invention is an ammunition magazine as defined by claim <NUM>.

In some embodiments, the present disclosure provides an ammunition magazine configured to bottom-feed a plurality of ammunition rounds into an upper receiver of a firearm, the ammunition magazine comprising: a magazine housing including an ammunition reservoir, a proximal guide channel disposed proximal to the ammunition reservoir, and lips disposed on a top surface of the magazine housing, the lips configured to align the ammunition reservoir with a feed ramp of the upper receiver; a spring within the magazine housing; a floor plate retainer disposed at a bottom end of the spring; a floor plate disposed at a bottom end of the magazine housing and reversibly mated with the floor plate retainer; and a magazine follower disposed at a top end of the spring, the magazine follower including a follower protrusion disposed on a superior portion of the magazine follower, and a bolt catch piston disposed at a proximal end of the magazine follower and configured to slide along the proximal guide channel of the magazine housing.

In other embodiments not covered by the claims, the present disclosure provides a bolt carrier for aligning a rimfire primer of an ammunition round with a centerfire firing pin of a firearm, the bolt carrier comprising: a bolt carrier body having a generally cylindrical cross-sectional shape and including a side-disposed extractor disposed on one side of the bolt carrier body, a centerfire bore disposed through the bolt carrier body and configured to enable a centerfire firing pin to slide therethrough, a forward assist adaptor disposed at a proximal end of the bolt carrier body and including a plurality of side-disposed ridges configured to temporarily engage with a forward assist piston of an upper receiver, a hold-open fin disposed on an inferior portion of the bolt carrier body and configured to engage with a bolt catch of a lower receiver of a firearm after a final ammunition round from the ammunition magazine is struck by the centerfire firing pin, and a rimfire alignment shoulder disposed on a distal end of the bolt carrier body and configured to align the centerfire bore with a rim of an ammunition round from the ammunition magazine; and a sleeve disposed on a superior portion of the bolt carrier body and configured to enable the bolt carrier to slide along a rod.

In other embodiments not covered by the claims, the present disclosure provides a kit comprising an ammunition magazine as disclosed herein and a bolt carrier as disclosed herein.

Referring generally to <FIG>, the present disclosure provides ammunition magazines and hold-open bolt carriers for using low-cost (e.g., 22LR) ammunition in a standard AR-<NUM> or M16 upper receiver.

Referring to <FIG>, ammunition magazines <NUM> consistent with the present disclosure are configured to removably mate with a lower receiver of a firearm, and to bottom-feed ammunition rounds into the upper receiver. The ammunition magazine <NUM> comprises a housing <NUM> that defines (e.g., includes) an ammunition reservoir <NUM>, a distal guide channel <NUM>, a recess <NUM>, a boss <NUM>, and lips <NUM>; a follower <NUM>; and a spring (not shown) configured to force the follower <NUM> towards a superior end of the ammunition magazine <NUM>.

The ammunition reservoir <NUM> is configured to retain a plurality of ammunition rounds. In some embodiments, the ammunition reservoir <NUM> is configured to retain the ammunition rounds in a single stack arrangement. In other embodiments, the ammunition reservoir <NUM> is configured to retain the ammunition rounds in a double stack arrangement. In some embodiments, the ammunition reservoir <NUM> is configured to hold at least about <NUM> ammunition rounds, for example <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, <NUM> ammunition rounds, or more than <NUM> ammunition rounds.

The distal guide channel <NUM> is disposed parallel to the ammunition reservoir <NUM> and is configured to receive a distal guide piston 153a of the follower <NUM>.

The recess <NUM> is disposed on the outside face of the ammunition magazine <NUM>. The boss <NUM> is disposed below the recess <NUM> on the outside face of the ammunition magazine <NUM>. The recess <NUM> and boss <NUM> are configured to mate with a magazine catch of the firearm.

The lips <NUM> are disposed on the superior end of the ammunition magazine <NUM> and are configured to guide the ammunition rounds from the ammunition reservoir <NUM> to the upper receiver. In some embodiments, such as those consistent with <FIG> and <FIG>, the lips <NUM> include a contoured superior edge profile that facilitates convenient addition of ammunition rounds to the ammunition reservoir <NUM>.

The magazine housing <NUM> further defines (e.g., includes) a floor plate receiver <NUM> disposed at the inferior end of the ammunition magazine <NUM> and configured to receive a floor plate (not shown).

The magazine housing <NUM> further defines (e.g., includes) a proximal guide channel <NUM> that is disposed parallel to the ammunition reservoir <NUM> and is configured to receive a bolt catch piston 153b of the follower <NUM>.

The magazine housing <NUM> further defines (e.g., includes) a channel <NUM> disposed through a side face or an end face of the magazine housing <NUM>. The channel <NUM>, when present, enables a loading tab (not shown) of the magazine follower <NUM> to protrude therethrough such that a user can apply force against the spring to ease loading of ammunition rounds into the ammunition reservoir <NUM>.

The magazine housing <NUM> further includes a storage compartment <NUM> disposed distal to the distal guide channel <NUM>. The storage compartment <NUM> may be used to store tools or accessories, for example, such as a tool including a tip configured to pass through the channel <NUM> in the magazine housing <NUM> and further configured to mate with the recess <NUM> of the follower <NUM> described more fully below.

Referring now to <FIG>, a follower <NUM> is disposed within the magazine housing <NUM> and is configured to separate the ammunition rounds from the spring. In general, the follower <NUM> comprises a follower protrusion <NUM> disposed on the superior portion of the follower <NUM>, a spring tang <NUM> disposed on the inferior portion of the follower <NUM>, and a body portion <NUM> including a bolt catch piston 153b disposed on the proximal end of the body portion <NUM>.

The follower protrusion <NUM> is generally wedge shaped, and includes an apex 151a at the distal end of the follower protrusion <NUM>. The wedge shape of the follower protrusion <NUM> is configured to assist feeding ammunition rounds to the feed ramp of the upper receiver of the firearm (not shown). In some embodiments, the wedge shape is defined by an angle α measured between the top surface 151b of the follower protrusion <NUM> and the top surface 153c of the body portion <NUM>. In such embodiments, the angle α may be about <NUM>° to about <NUM>°, for example about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, or about <NUM>°. In some embodiments, the angle α is about <NUM>° to about <NUM>°, for example about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, about <NUM>°, or about <NUM>°. In some embodiments, the angle α is about <NUM>°.

The spring tang <NUM> is configured to mate with the spring.

The body portion <NUM> includes a distal guide piston 153a disposed on the distal end of the body portion <NUM>. The distal guide piston 153a has a size and shape complementary to the distal guide channel <NUM> such that the distal guide piston 153a may slide along the distal guide channel <NUM>.

The body portion <NUM> further includes a bolt catch piston 153b disposed on the proximal end of the body portion <NUM> and having a size and shape complementary to the proximal guide channel <NUM> such that the bolt catch piston 153b may slide along the proximal guide channel <NUM>. The bolt catch piston 153b is further configured to force upwards the bolt catch of the upper receiver after a final ammunition round is fed from the ammunition reservoir <NUM> to the upper receiver.

In some embodiments, the body portion <NUM> further includes a recess <NUM> disposed in a side wall. In such embodiments, the recess <NUM> may be positioned in the side wall such that the recess <NUM> aligns with the channel <NUM> of the magazine <NUM>. The recess <NUM> is configured to receive a tool (not shown) through the channel <NUM>. When engaged with the recess <NUM> through the channel <NUM>, the tool enables a user to force the follower <NUM> up or down within the magazine <NUM> without removing the magazine <NUM> from a firearm receiver, for example to dislodge jammed ammunition cartridges within the magazine <NUM>.

Referring now to <FIG>, bolt carriers <NUM> consistent with the present disclosure generally comprise a bolt carrier body <NUM>, a sleeve <NUM> disposed on the superior portion of the carrier body <NUM>, and a hold-open fin <NUM> disposed on the inferior portion of the bolt carrier <NUM>.

The bolt carrier body <NUM> has a generally cylindrical cross-sectional shape and is configured to mate with the bolt (not shown). The bolt carrier body <NUM> includes a side-disposed ejector <NUM> configured to eject the casing of a spent ammunition round from the upper receiver. The bolt carrier body <NUM> further includes a forward assist adaptor <NUM> disposed at its proximal end. The forward assist adaptor <NUM> includes a plurality of side-disposed ridges <NUM> configured to engage with a forward assist assembly (not shown).

The bolt carrier body <NUM> includes a centerfire bore <NUM> disposed longitudinally through the bolt carrier body <NUM>, and configured to enable a firing pin (not shown) to slide therethrough upon activation of a trigger mechanism of the firearm (not shown).

The bolt carrier body <NUM> further includes a rimfire alignment shoulder <NUM> disposed on its distal end. The rimfire alignment shoulder <NUM> defines a rimfire alignment contour 32a that engages the rim (e.g., the rim primer) of an ammunition round that has been fed from the magazine <NUM> to the upper receiver to align the rim of the ammunition round with the centerfire bore <NUM> such that the firing pin strikes the rim of the ammunition round instead of the central portion of the ammunition round, as would be the case if a. <NUM> or <NUM> ammunition round were fed into a standard AR <NUM> or M16 bolt carrier body.

The bolt carrier <NUM> further includes a hold-open fin <NUM> disposed on its inferior portion. The hold-open fin <NUM> includes an engagement face 200a on its distal end. The engagement face 200a is configured to engage with the follower protrusion <NUM> (e.g., the apex 151a) of the follower <NUM> after the last ammunition round has been fed from the magazine reservoir <NUM> into the upper receiver and activated by the firing pin.

In some embodiments, the present disclosure provides an ammunition magazine <NUM> configured to bottom-feed a plurality of ammunition rounds into an upper receiver of a firearm, the ammunition magazine <NUM> comprising: a magazine housing <NUM> including an ammunition reservoir <NUM>, a proximal guide channel <NUM> disposed proximal to the ammunition reservoir <NUM>, and lips <NUM> disposed on a top surface of the magazine housing <NUM>, the lips <NUM> configured to align the ammunition reservoir <NUM> with a feed ramp of the upper receiver; a spring within the magazine housing <NUM>; a floor plate retainer disposed at a bottom end of the spring; a floor plate disposed at a bottom end of the magazine housing <NUM> and reversibly mated with the floor plate retainer; and a magazine follower <NUM> disposed at a top end of the spring, the magazine follower <NUM> including a follower protrusion <NUM> disposed on a superior portion of the magazine follower <NUM>, and a bolt catch piston 153b disposed at a proximal end of a body portion <NUM> of the magazine follower <NUM> and configured to slide along the proximal guide channel <NUM> of the magazine housing <NUM>. In some embodiments, the magazine <NUM> further includes a distal guide channel <NUM> disposed distal to the ammunition reservoir <NUM>, and wherein the magazine follower <NUM> further includes a distal guide piston 153a disposed at a distal end of the body portion <NUM> and configured to slide along the distal guide channel <NUM>. In some embodiments, the ammunition magazine <NUM> further comprises a channel <NUM> disposed through the magazine housing <NUM>, and wherein the follower <NUM> further includes a loading tab configured to slide along the channel <NUM>. In some embodiments, the ammunition round is a 22LR round. In some embodiments, the magazine follower <NUM> further includes a spring tang disposed on an inferior portion of the magazine follower <NUM>, wherein the spring tang is configured to engage with the top end of the spring. In some embodiments, the distal catch piston 153a has a generally cylindrical or truncated cylindrical cross-sectional shape. In some embodiments, the bolt catch piston 153b has a rounded rectangular or squircle cross-sectional shape. In some embodiments, the bolt catch piston 153b is configured to engage a bolt catch of a lower receiver of a firearm after a final ammunition round is fed from the ammunition reservoir <NUM> into the upper receiver.

In some embodiments not covered by the claims, the present disclosure provides a bolt carrier <NUM> for aligning a rimfire primer of an ammunition round with a centerfire firing pin of a firearm, the bolt carrier <NUM> comprising: a bolt carrier body <NUM> having a generally cylindrical cross-sectional shape and including a side-disposed extractor <NUM> disposed on one side of the bolt carrier body <NUM>, a centerfire bore <NUM> disposed through the bolt carrier body <NUM> and configured to enable a centerfire firing pin to slide therethrough, a forward assist adaptor <NUM> disposed at a proximal end of the bolt carrier body <NUM> and including a plurality of side-disposed ridges <NUM> configured to temporarily engage with a forward assist piston of an upper receiver, a hold-open fin <NUM> disposed on an inferior portion of the bolt carrier body <NUM> and configured to engage with a bolt catch of a lower receiver of a firearm after a final ammunition round from the ammunition magazine <NUM> is struck by the centerfire firing pin, and a rimfire alignment shoulder 32a disposed on a distal end of the bolt carrier body <NUM> and configured to align the centerfire bore <NUM> with a rim of an ammunition round from the ammunition magazine <NUM>; and a sleeve <NUM> disposed on a superior portion of the bolt carrier body <NUM> and configured to enable the bolt carrier <NUM> to slide along a rod (not shown). In some embodiments, the rimfire alignment shoulder 32a includes an arcuate rimfire alignment contour configured to engage the rim of the ammunition round.

In some embodiments not covered by the claims, the present disclosure provides a kit comprising an ammunition magazine <NUM> as disclosed herein, and a bolt carrier <NUM> as disclosed herein. In some embodiments, the ammunition reservoir <NUM> is configured to retain <NUM> ammunition rounds. In some embodiments, the ammunition rounds are 22LR rounds.

A magazine with follower consistent with the magazines and followers of <FIG> was constructed using PLA filament and a commercially available 3D printer. The follower was placed into the ammunition reservoir and a compression spring was disposed between the spring tang and the bottom inside surface of the ammunition reservoir.

22LR ammunition cartridges were then top-loaded one-by-one into the ammunition reservoir through the lips until the ammunition reservoir was filled to capacity in a single stack configuration.

The magazine was mated with a receiver of an AR15 style rifle including a bolt consistent with the hold-open bolt of <FIG>. The LR22 ammunition cartridges were fired one-by-one through the rifle. When the LR22 ammunition cartridges were properly loaded into the magazine reservoir (i.e., with the rim of each LR22 ammunition cartridge disposed distal to the rim of the LR22 ammunition cartridge immediately below), no misfires or jams were observed when the receiver, and the LR22 cartridges did not jam within the ammunition reservoir.

Claim 1:
An ammunition magazine (<NUM>) configured to bottom-feed a plurality of ammunition rounds into an upper receiver of a firearm, the ammunition magazine (<NUM>) comprising:
a magazine housing (<NUM>) including:
an ammunition reservoir (<NUM>),
a proximal guide channel (<NUM>) disposed proximal to the ammunition reservoir (<NUM>),
a distal guide channel (<NUM>) disposed parallel to the ammunition reservoir (<NUM>), and
lips (<NUM>) disposed on a top surface of the magazine housing (<NUM>), the lips (<NUM>) configured to align the ammunition reservoir (<NUM>) with a feed ramp of the upper receiver;
a spring within the magazine housing (<NUM>);
a floor plate retainer (<NUM>) disposed at a bottom end of the spring;
a floor plate disposed at a bottom end of the magazine housing (<NUM>) and
reversibly mated with the floor plate retainer (<NUM>); and
a magazine follower (<NUM>) disposed at a top end of the spring, the magazine follower (<NUM>) including:
a follower protrusion (<NUM>) disposed on a superior portion of the magazine follower (<NUM>), and
a bolt catch piston (153b) disposed at a proximal end of a body portion (<NUM>) of the magazine follower (<NUM>) and configured to slide along the proximal guide channel (<NUM>) of the magazine housing (<NUM>);
characterized by a distal guide piston (153a) disposed at a distal end of the body portion (<NUM>) of the magazine follower (<NUM>), the distal guide piston (153a) having a size and shape complementary to the distal guide channel (<NUM>) of the magazine housing (<NUM>) and configured to slide along the distal guide channel (<NUM>);
wherein the magazine housing (<NUM>) further comprises a storage compartment (<NUM>) disposed distal to the distal guide channel (<NUM>).