Ammunition and explosives – Projectiles – Having jacket
Reexamination Certificate
1998-10-05
2001-07-10
Carone, Michael J. (Department: 3641)
Ammunition and explosives
Projectiles
Having jacket
C102S517000
Reexamination Certificate
active
06257149
ABSTRACT:
The present invention relates to a bullet, and in particular to a lead-free bullet that will retain the markings of the barrel of a firearm after the bullet is fired from the firearm. As used herein, a “firearm” is intended to include rifles, pistols, guns and the like.
Firearms are used in a wide variety of ways, including hunting and other sporting activities, law enforcement activities and military activities. In hunting activities, spent bullets or parts of spent bullets remain in the environment. They may be eaten by game, or other animals or birds, either inadvertently or out of curiosity. This can cause poisoning effects, depending on the type of bullet. In addition, if the bullet is a frangible bullet, parts of the bullet will be scattered through the flesh of the game on impact, posing a potential danger to humans if the flesh is eaten or result in poisoning of the injured animal and the likelihood of a slow death. If the bullets contain lead, such poisoning and environmental effects pose significant concerns about health issues, and have resulted in governmental regulations banning the use of lead in such bullets.
In sporting activities and other testing of bullets e.g. in the firing of firearms at a firing range, lead-containing bullets are a health hazard in that fumes of lead are dispersed into the atmosphere on impact of the bullet on the target or wood or other material behind the target. The resultant haze is hazardous to the health of persons using the firing range, or employed in the firing range, and restrictions may be required on the amount of time that may be spent by a person at or on a firing range. Thus, even though bullets may be collected from a firing range in order that the materials from which the bullets are formed may be recycled, fumes from lead-containing bullets are a major health hazard.
In law enforcement activities, there is a need to be able to relate fragments of a bullet found at a crime scene to the firearm that was used to fire the bullet. Such a correlation is often important evidence in obtaining a conviction. The barrel of a firearm imparts markings to the outside of a bullet in the form of scratches, barrel rifling pattern or other marks, effectively a signature of the firearm. It is this signature that can be used in law enforcement to identify the firearm that was used to fire a particular bullet. However, to do so, it is essential that the bullet be capable of accepting and retaining such markings. This must occur even if the bullet is frangible, in which case law enforcement authorities must work with only particles or fragments of the bullet.
In military activities, bullets must be capable of being used in rapid-firing firearms, without causing jamming of the firearm during use.
Bullets may be categorized as being frangible bullets or non-frangible bullets. The latter may substantially retain their shape on impact or become distorted in shape on impact without fragmentation. Frangible bullets are intended to break apart on impact.
Some firearms are reloaded by mechanical means, for instance the use of a bolt action to eject the shell of a spent bullet and insert a new bullet into the firing chamber of the firearm. For firearms that are reloaded by such mechanical means, the weight of the bullet has little significant bearing on the reloading of the firearm. However, other firearms are automatic firearms, in which case the firing of one bullet actuates mechanisms for ejection of the spent shell and insertion of the next bullet into the firing chamber, often in a very rapid manner. Such mechanisms may, for instance, be actuated directly by pressure generated from the barrel or gas activated using gas obtained from the barrel. In both cases, the weight of the bullet must be sufficient to create a pressure within the barrel during the firing of the bullet that is sufficient to actuate the mechanisms for ejection of the shell and insertion of the next bullet into the firing chamber.
After the firing of a bullet in a firearm having an automatic reloading mechanism, the next round is inserted into the firing chamber pending the next firing of a further bullet. In rapid-firing firearms, the barrel of the firearm may become very hot, depending in particular on the number of bullets fired in a sequence, and consequently the bullet loaded into the firing chamber may become hot. Thus, bullets intended for rapid-firing firearms must have properties that will withstand the temperatures to which the bullet might be subjected in the firing chamber, without softening of any casing, fragmentation of a non-frangible bullet or other deleterious effects that might cause malfunctioning of the firearm, poor trajectory of the bullet or other problems.
Lead-free bullets are known. For instance, U.S. Pat. No. 5,399,187 discloses a bullet formed from tungsten, or an alloy of tungsten, and phenol formaldehyde or polymethylmethacrylate polymers. U.S. Pat. No. 5,012,743 discloses a light weight elongated projectile formed from a casing of copper alloy, steel or similar material and a lower density core e.g. polycarbonate or polyamide. WO 95/23952 discloses a projectile having a core of polyethylene and iron. DE-U-9209598 discloses a bullet formed from a plastic viz. polypropylene homopolymer, and a metal jacket. U.S. Pat. No. 4,503,777 discloses a lead bullet manufactured by the pouring of lead. Projectiles formed from bismuth alloys are disclosed in WO 92/08097 and WO 95/08748.
Bullets that are free of lead are strongly preferred both for environmental and health reasons, and in many instances are required by governmental regulations. Thus, there is a need for lead-free bullets, and especially for such bullets that will retain the signature of a barrel on firing. Such bullets have now been found.
Accordingly, one aspect of the present invention provides a bullet that will retain markings from a firearm barrel when fired from such firearm, comprising:
a right cylindrical core with opposed ends, one such opposed end having a tapered section integrally connected thereto, said core being formed from a lead-free composition comprising a polymer selected from amorphous or low crystallinity polymer, said composition retaining it's integrity when fired from the firearm, said right cylindrical core having a jacket that is cylindrical and formed from a thermoplastic polymer or copper, said thermoplastic polymer having a softening point above firearm barrel temperatures, said bullet preferably having a weight that is at least 80% of the weight of a comparable lead bullet.
In preferred embodiments of the invention, the adhesion between the jacket and the core is sufficient to retain the integrity of the bullet on firing until impact, preferably being such that the jacket and core separate on impact.
In another embodiment, the polymer of the core is selected from ethylene/methacrylic acid copolymer ionomers, polyetherester elastomers and polyamides.
In yet another embodiment, the mass of the bullet is sufficient to actuate firearm reloading mechanisms.
In other embodiments, the tapered section is a truncated cone, parabolic or rounded, including such shapes having a so-called “hollow point”.
In a further embodiment, the jacket of the bullet extends over the tapered section attached to one end of the right cylindrical core.
In a still further embodiment, the other of the opposed ends is a truncated tapered section.
In a preferred embodiment, the jacket at the other end of the opposed ends is curled inward towards the tip, especially with the remainder of said end being free of jacket.
In another aspect of the invention there is provided a bullet in a shell, said bullet comprising a right cylindrical core with opposed ends, one such opposed end having a tapered section integrally connected thereto, said core being formed from a lead-free composition comprising a polymer selected from amorphous or low crystallinity polymer, said composition retaining it's integrity when fired from the firearm, said right cylindrical core having a jacket that is cylindrical an
Baker Aileen J.
Carone Michael J.
Cesaroni Technology, Inc.
Gifford, Krass, Groh Sprinkle, Anderson & Citkowski, P.C.
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