US Cartridge, 37mm APC-T, M51, M51B1, M51B2
This round has all of the features of an ideal armor-piercing shot, and is effective against all types of armor plate. The model number marked on the projectile may be either M51, M51B1 or M51B2; rounds so marked are identical in functioning, the B1 or B2 designations signifying only that the projectiles are manufacturing alternatives of the M51.
The projectile is made up of four parts:
1. The body is made of very hard steel and does the actual penetrating. It is solid except for a cavity in the base to contain the tracer.
2. The cap is made of soft steel and is sweated on the nose of the body. Its purpose is to reduce the possibility of ricochet and to serve as a cushion or guide for the body when it strikes the armor plate.
3. The windshield is a false ogive, made of an aluminum alloy, which is assembled to the cap with threads, and continues the nose of the projectile to a point. Its purpose is to streamline the projectile in flight, thus improving its ballistics.
4. The tracer is made up of red tracer composition, and igniting composition, and a celluloid cup which fits over the tracer charge and is sealed with adhesive compound. The tracer burns for about 2,000 yards of the flight of the projectile.
Nothing else to see.