or jacket is first tinned on the inside and then the lead is cast in,
thus melting the tin and adhering firmly to the jacket. This projectile
sets up enormous friction in the barrel of the gun when used with
smokeless powder; as the smokeless powder leaves the gun barrel
perfectly clean and the two steel surfaces being in absolute contact
cause tremendous friction; and as the coefficient of friction varies
with every shot, the pressure in the gun constantly varies greatly.

The German silver covered bullet used by the French has the disadvantage
that when firing rapidly the chamber of the barrel becomes nickel plated
and great friction is caused, mounting up the pressures and causing the
muzzle velocities to fall off.

The Austrians, in order to prevent their steel cased bullets from
rusting and to lessen the friction in the barrel of the gun, cover them
with a heavy lubricant, which gives the cartridges an unsightly
appearance and causes them to gather dust and sand. The French employ a
lubricant at the base of the projectile, with a small copper disk
between the same and the powder.

Col. A.R. Buffington, commander of the National Armory at Springfield,
Mass., has made a steel covered projectile which he prevents from
rusting by blackening by a niter process. Several grooves are pressed in
the base of the bullet which carry a lubricant, and when the bullet is
inserted in the cartridge case the grooves are covered by it.
Furthermore, these grooves prevent the lead filling from bursting
through the steel casing, leaving the latter in the barrel, as often
occurs with the Austrian and French projectiles when using smokeless
powder.