From TM 43-0001-27, ARMY AMMUNITION DATA SHEETS, SMALL CALIBER AMMUNITION FSC 1305 dated April 1994, page 8-13,
Cartridge, Caliber .45, Ball, M1911:
Use:
Submachine Gun, Caliber .45, M3A1; and Pistol, Caliber .45, M1911A1. The cartridge is intended for use against personnel.
Description:
BALL Cartridge. The cartridge is identified by the plain bullet tip.
Propellant:
Type ------------ SR 7970
Weight---------- 5 gr
Performance:
Chamber pressure----- 19,000 psi
Velocity ---------------- 885 ± 25 fps, 25.5 ft from muzzle
That compares with current SAAMI specs for the 45acp of 21,000 psi and 45 acp+P of 23,000 psi.