A firearm cartridge system is provided and includes a case with a neck portion, body portion, shoulder portion, a base portion, and a indentation. The neck portion has a diameter between about 0.249 in to about 0.256 in. The body portion tapers from a first end having a diameter between about 0.465 in to about 0.475 to a second end having a diameter between about 0.449 in to about 0.458 in. The shoulder portion connects the body portion and neck portion and has a diameter between about 0.395 in to about 0.405 in. The base portion is positioned on the second end of the body portion and has diameter between about 0.463 in to about 0.477 in. The indentation joins the body portion and the base portion and includes a sidewall with angle between 30° to 42°.

A low energy cartridge has a case having a sidewall with an interior surface defining a projectile receptacle along a bore axis and having a forward open case mouth, a projectile having an exterior sidewall closely received in the projectile receptacle and defining a rotational axis, a propellant receptacle defined by the case and having a passage communicating with the projectile receptacle, the projectile exterior sidewall being non-circular in cross section across the rotational axis, and the case sidewall interior surface having a rotational engagement feature configured to rotationally engage the non-circular projectile exterior sidewall. The projectile may be slidably received in the projectile receptacle for propulsion from the forward open case mouth. At least one of the projectile and the sidewall interior surface may have a helical surface feature, such that spin is imparted to the projectile upon propulsion from the case.

The present disclosure is directed to firearms that can receive and fire bullets from ammunition with different cartridge case sizes. For example, the receiver may fire a bullet from either a short cartridge, a medium cartridge, or long cartridge after the short, medium, or long cartridge is received by a receiver of the firearm. This firearm may include a receiver portion and a bolt portion that lock together at different relative locations when cartridges of different lengths are received by the receiver portion. The receiver portion may include a first type of alignment retention features (e.g. protrusions) and the bolt portion may include a second type of alignment retention features (e.g. recessions). Once a firearm cartridge is located inside of the firearm, it may be fired based on the receiver and the bolt portions being locked together via physical engagement of the different types of alignment retention features.

Ammunition cartridge comprising a rigid casing including a tubular sleeve and a base closing an end of the casing, a projectile mounted at another end of the casing, a propellant charge contained inside the casing, and an ignition device. The projectile comprises a solid material body having a volume V1 extending between a tip to a trailing end, wherein the projectile further comprises a cavity that extends into the body from the trailing end, a volume V2 of the cavity being at least fifteen percent (15%) of a combined volume V1+V2 of the projectile solid material and cavity: V2>0.15×(V1+V2).

The present invention provides a method for chambering a barrel of a gun comprising the steps of: providing a chamber reamer comprising a shank extending longitudinally between a front end and a rear end and having a plurality of cutting flutes disposed between the front end and the rear end; a shaft extending to the rear end of the shank and adapted to rotate the shank along an interior of the barrel to form a chamber therein, wherein the shank comprises a body region that extends to a shoulder region that transitions to a case mouth that extends to a throat connected to a free bore, wherein the body region comprises a rear diameter near the breech face of about 0.4718; and a body shoulder junction diameter of about 0.4625; wherein the shoulder region comprises a shoulder case mouth junction diameter is between 0.31 to 0.32; a breech face to lead-in bore junction length of between 2.1 to 2.2; a breech face to body-shoulder junction length of between 1.80-1.85; and a breech face to shoulder neck junction length of between 1.9-2.0; aligning the chamber reamer with a barrel in which a chamber is to be formed; rotating the chamber reamer; and pushing the chamber reamer into the barrel to from a chamber in the barrel.

The present invention provides a barrel of a firearm, comprising: a barrel bore being defined within said barrel; a cartridge chamber being defined within said barrel from a head face to said barrel bore, said cartridge chamber having a generally tapered internal body wall surface; a cartridge case shoulder support surface; wherein the cartridge case shoulder support surface has a shoulder taper angle of about 30 degrees; and a shoulder transition connecting the cartridge case shoulder support surface to a throat in communication with the barrel bore, wherein the shoulder transition has a radius of circular curve convex segment 138 and a radius of circular curve concave segment 140.

One embodiment of the present invention provides a polymeric ammunition having a metal injection molded primer insert.

A ballistically enhanced projectile 360, 460 includes a body having a distal ogive section with external ballistic effect uniforming surface discontinuity (e.g., nose ring groove 369, 469) defined therein to provide an unsupported gap in the ogive profile which affects the flow of air over the front half of the ogive to provide greater aerodynamic uniformity and shot-to-shot consistency with more uniform observed external ballistics and superior terminal ballistics. The bullet's external surface discontinuity feature (369 or 469) creates effects in the flowfield that dominate any dynamic effects from bullet-to-bullet manufacturing inconsistency and resultant differences in dynamic behavior.

Disclosed are a projectile and a method of its manufacture for the field of investigating the strength properties of a solid material by application of a mechanical force and more particularly for bird strike tests consisting of a gel including glycerol. A projectile 1 according to the invention may have a central portion 4 of cylindrical shape including a substantially hemispherical portion 2, 3 at each of the ends thereof.