Teflon coated bullet
|
|
Certain varieties of handgun and rifle bullets are coated with a lubricant such as Teflon.
Ammunition for handgun and rifles contains several parts. Bullets (the projectile) that are usually made out of lead, or have a lead core wrapped in a copper jacket.
Rapid burning of the propellant in ammunition creates high pressure gas that exerts pressure on the base of the bullet, thus accelerating it down the firearm's barrel towards the muzzle. During the entire journey down the barrel, the bullet remains in contact with the barrel. In rifled barrels (the norm for pistols, rifles, and some shotguns), the bullet diameter is actually slightly larger than the barrel diameter, so as to force the bullet to deform into shallow helices machined into the interior of the barrel, thus spinning the bullet for later flight stabilization. After exiting the muzzle, the bullet continues down range because of its momentum. Muzzle velocities for common sporting bullets range from 500 ft/s (150 m/s) up to 4,000 ft/s (1,200 m/s).
At velocities much above 800 ft/s (250 m/s), the friction that a bullet squeezing down a barrel experiences is sufficient to deform, or even rip apart a pure lead bullet. Additionally, even below this threshold, a pure lead bullet forced down a barrel will leave minor deposits of lead known as leading. Leading is undesirable because it degrades the accuracy of subsequent shots, and because removing it from a barrel is an unpleasant task.
Thus, if one wants to fire ammunition at faster than 800 ft/s, or below that speed but without fouling a barrel with lead, one must find a way to strengthen the bullet, and/or lower the friction between the bullet and the barrel.
The former approach leads to jacketed bullets, where the lead core of a bullet is wrapped inside a form-fitting jacket of a harder metal, usually copper or gilding metal.
The latter approach leads to lubrication of bullets.
Molybdenum disulfide ("moly") is one lubricant that is widely used in industry, and has had some noteworthy acceptance in shooting circles.
Teflon is another such lubricant, and bullets coated in which had an interesting political saga in the United States. They were first introduced in the 1960s by three law enforcement officers who worked together to develop new ammunition for police use. The first Teflon coated bullets were known as "KTW bullets", after the initials of the three inventors, and were sold only to law enforcement organizations.
In 1982, the NBC TV network ran a special on the bullets and argued that the bullets were a threat to police. Gun control organizations in the US labelled Teflon coated bullets as "cop killer bullets", and argued that they were capable of penetrating Kevlar bullet-resistant vests. This was, in a sense, true: many of the bullets that had Teflon coatings were capable of penetrating Kevlar vests...but they would be equally capable of penetrating the vests without Teflon coating: the coating has no effect on the ability of a bullet to punch through body armor.