Forty five ACP cartridge. Thompson’s Trench Broom strike several snags in progress, as neither a gas-operated system nor a straight blowback proved suitable for what he envisioned. What he wanted was a retarded blowback method. Developed only being an "overstamped" model (an arsenal-refurbished M1 with new rear sight along with https://robertog890ndq8.eqnextwiki.com/user