Firearm projectile

A projectile adapted for use with a cartridge in a firearm with a barrel. The projectile is of a .22 caliber. The projectile includes a body machined from a solid material having a rear end and forward end. The projectile includes a heel starting at the rear end. A crimp groove extends forward of the heel. An adjustable sealing band extends forward of the crimp groove. A pressure reducing groove extends forward of the rear driving band. A front driving band extends forward of the pressure reducing groove. An Ogive extends forward of the front driving band. Finally, there is a bullet tip extending forward of the Ogive. A specific version ment that has been found to be very accurate in the most amount of rifles has adjustable sealing band diameter of 0.224 inches, a pressure reducing groove diameter of 0.2165 inches and a front driving band diameter of 0.2213 inches.

BACKGROUND

The present invention generally relates to firearm projectiles. More specifically, the present invention relates to .22 caliber rimfire bullets.

With the advent of laws restricting use of lead bullets and lead core jacket bullets, shooters are turning to the use of bullets machined from a solid material. Gyroscopic stability problems are associated with jacketed lead bullets due to the core of the bullet not being located at the true axis of rotation of the bullet, as compared to precision machined solid bullets. Some firearms include rifling within the barrel of the firearm. Rifling is a series of grooves cut into inside diameter of the barrel. The remaining material between the grooves is knows as the lands. The lands are what remain between the grooves after the grooves are cut in the inside diameter of a blank barrel. Lead and lead core jacketed bullets are designed to be slightly undersize due to swelling when the bullet is fired to seal into the groove diameter of a barrel of a firearm. Whereby, groove diameter is the largest diameter inside the barrel of the firearm.

The .22 caliber bullet commonly uses a heeled lead or lightly plated bullet. The nominal bullet diameter of the .22 caliber bullet is larger than the nominal bore diameter of a firearm to prevent fliers, or inaccuracies, that can occur when shooting lead bullets that are the same or slightly smaller than the groove diameter. SAAMI specifies a nominal bullet diameter of 0.2255 with a tolerance of −0.004, while the specified bore diameter is 0.222. In practice, 0.224 or slightly larger bullets are common, with barrel groove diameters commonly around 0.223. Having a heeled bullet means that the bullet is the same diameter as the cartridge case and has a narrower “heel” portion that fits in the cartridge case. The .22 Long Rifle cartridge is one of the few cartridges that are accepted by a large variety of rifles and handguns where the bullet diameter is in the range of 0.223 inches (5.7 mm)-0.2255 inches (5.73 mm).

Machining monolithic bullets from solid material instead of forging lead bullets requires different design criteria. Solid bullets cannot be shot in standard .22 caliber rimfire barrels if manufactured to the same OD tolerance as solid lead bullets are manufactured. Bullets machined from copper or a copper alloy are substantially harder than lead bullets and excess pressure occurs if made to the same diameter as the lead bullets. Therefore the OD must be made slightly smaller than the rifle barrels groove diameter. If the solid bullets are not “sealed” in the rifle grooves during firing, gasses escape around the bullet causing inaccuracies to be experience when using solid bullets in some guns. When there is no sealing between the solid bullet and the barrel there can also be loss of potential speed of the bullet as it leaves the barrel. Solid copper bullets do not upset or swell to fill the groove diameter. If there is any wear in the barrel or if the barrel is made slightly oversize due to the manufacturing process, blow by is experienced using solid copper bullets. Blow by is where pressure escapes around the bullet. That is why shooters using solid copper bullets in the past have not been able to shoot them consistently. Typically in shooting five solid copper bullets, you may get three or four with in a group and one or two that are not in the group of the other shots. On top of the difference between the design of lead based bullets versus solid bullets, .22 caliber rimfire bullets design is a different approach, then the typical centerfire caliber bullet. This is due to the cartridge case used and manufacturing process.

It is an object of the present invention to provide a .22 caliber rimfire bullet of a solid material that has improved accuracy.

SUMMARY OF THE INVENTION

A projectile adapted for use with a cartridge in a firearm with a barrel. The projectile is of a .22 caliber. The projectile includes a body machined from a solid material having a rear end and forward end. The projectile includes a heel starting at the rear end. A crimp groove extends forward of the heel. An adjustable sealing band extends forward of the crimp groove. A pressure reducing groove extends forward of the rear driving band. A front driving band extends forward of the pressure reducing groove. An Ogive extends forward of the front driving band. Finally, there is a bullet tip extending forward of the Ogive. A specific version that has been found to be very accurate in the most amount of rifles has adjustable sealing band diameter of 0.224 inches, a pressure reducing groove diameter of 0.2165 inches and a front driving band diameter of 0.2213 inches.

DETAILED DESCRIPTION

The present invention is a firearm projectile10for a firearm, commonly referred to as a bullet. The firearm projectile is of a monolithic construction, which is the precise machining of a bullet from a solid material such as copper. The bullet is manufactured by turning on a lathe or milling with a CNC machine. The caliber of the bullet is .22 caliber for a rimfire cartridge case. The projectile eliminates several problems associated with other solid bullet designs for the .22 caliber bullet, as well as problems associated with lead core jacketed bullets.FIG. 1shows a first embodiment,FIGS. 2-3shows a second embodiment andFIG. 4shows a third embodiment.

FIG. 1shows the profile of the first embodiment of the projectile10depicting the componential shapes of the first embodiment of the bullet. The projectile10includes a rear end12and a forward end14. The components of the bullet profile starting from the rear12are a heel16, crimp groove18, rear driving band20, pressure reducing groove22, front driving band24, Ogive26and bullet tip28. The components of the bullet profile can be defined by a diameter and length, where length is a measurement between the front end14and the rear end12of the bullet profile. An optional bore rider30is also shown onFIG. 2. Due to the ductility and formable nature of the copper and copper alloys typically used for bullets, these materials allow deformation of the bullet during the process of firing. The pressure reducing groove22is for reducing the total length of the bearing surface and also provides an area to receive the transfer of any deformed material of the projectile10during the process of projecting the projectile10through a barrel of a firearm. The crimp groove18of the projectile10serves two purposes. The first purpose is that the crimp groove18is used in the process of crimping the case to the projectile10. The second purpose is that the crimp grove18serves as a secondary area to receive deformed material of the projectile10.

A chamfer32is at the rear end12as part of the heel16. The chamfer32provides a starting place that is slightly smaller diameter than the heel16to ease insertion of the projectile10into the case. The heel16has a range of diameter of 0.205-0.209 inches and a length in a range of 0.069±0.015 inches. The heel16is the component of the profile of the projectile10that is inserted in the case to form a complete cartridge that is ready to be fired by a firearm. The crimp groove18is forward of the heel16. The crimp groove18has a range of diameter of 0.200-0.208 inches and a length in a range of 0.034±0.025 inches. The rear driving band20is forward of the crimp groove18. The rear driving band20has a range of diameter of 0.221-0.222 inches and a length in a range of 0.016±0.025 inches. The pressure reducing groove22is forward of the rear driving band20. The pressure reducing groove22has a range of diameter of 0.210-0.221 inches and a length in a range of 0.051±0.025 inches. The front driving band24is forward of the pressure reducing groove22. The front driving band24has a range of diameter of 0.219-0.222 inches and a length in a range of 0.020±0.015 inches. The Ogive26is forward of the front driving band24and the bullet tip28is at the front end14when the Ogive26ends. The Ogive26defined as the “curve of a bullet's forward section” and can be expressed as a tangent ogive or secant ogive. A bullet with a tangent Ogive is one that has the cylindrical surface of the bullet tangent, or blended smooth, to the body diameter of the bullet. A bullet with a secant Ogive is one that has the cylindrical surface of the bullet secant, or not blended smooth to the body of the bullet. The projectile is shown with a meplat as the bullet tip28, which is defined as a flat or open tip on the front end14of a bullet. The bullet tip28of the projectile10can also end in a round nose, a sharp tip or point.

FIG. 2shows the profile of the projectile10depicting the componential shapes of the second embodiment of the bullet.FIG. 3shows a perspective view ofFIG. 2. The profile of the projectile10inFIG. 2is the same asFIG. 1, but includes a bore rider30. A bore rider30is a section of the bullet where the diameter is that of the actual rifle barrels bore or slightly smaller which reduces the effective bearing surface length which in turn reduces pressures. The bore rider30is between the front driving band24and the Ogive26. The bore rider has a range of diameter of 0.214-0.219 inches and a length in a range of 0.124±0.120 inches depending on bullet weight.

FIG. 4shows the profile of the projectile10depicting the componential shapes of the third embodiment of the bullet. The profile of the projectile10inFIG. 4is the same asFIG. 1, but replaces the rear driving band20with an adjustable sealing band34. Due to the ductility and formable nature of the copper and copper alloys, these materials allow deformation of the adjustable sealing band, without causing excessive pressures or wear on the firearm. The adjustable sealing band34adjusts during firing by deforming. The adjustable sealing band34is larger than the driving band. The crimp groove18and pressure reducing groove22are each next to the adjustable sealing band34to receive part of the adjustable sealing band34when the adjustable sealing band34is deformed and also reduces the effective bearing surface length of the projectile10. The adjustable sealing band34is used to eliminate the possibility the projectile10will not seal tightly in the barrel of the firearm. When the adjustable sealing band34contacts the inside surfaces of a firearm, the adjustable sealing band34deforms to fit tightly within the rifled barrel of the firearm and forms a seal between the projectile10and the rifled barrel. A rifled barrel includes lands and groove twisted through the barrel. The seal forms between the projectile10and the rifled barrel due to the deformation of the adjustable sealing band34and prevents the escape of gases from behind the projectile10during firing. The adjustable sealing band34will flow into both the crimp groove18and pressure reducing groove22, as the adjustable sealing band34is compressed and deformed due to contact with the inside surfaces of the firearm. The adjustable sealing band34has a range of diameter of 0.222-0.226 inches and a length in a range of 0.016±0.020 inches. A specific version of the fourth embodiment that has been found to be very accurate in the most amount of rifles has adjustable sealing band diameter34of 0.224 inches, a pressure reducing groove24diameter of 0.2165 inches and a front driving band diameter24of 0.2213 inches. The third embodiment can include a bore rider30as described for the second embodiment.

While different embodiments of the invention have been described in detail herein, it will be appreciated by those skilled in the art that various modifications and alternatives to the embodiments could be developed in light of the overall teachings of the disclosure. Accordingly, the particular arrangements are illustrative only and are not limiting as to the scope of the invention that is to be given the full breadth of any and all equivalents thereof.