Thompson Submachine Gun (M1928A1) (replica of automatic weapon) (Auto-Ordinance Corp.); Cal .45 (11.4 mm); weight 10 lb 12 oz, 4.88 kg; length 33.7 in, 857 mm; barrel length 10.5 in, 267 mm; Operation – Blish Lock or blowback; magazine – 30 round capacity (50/100 round drum, 20/30 round clip); Rate of fire 700 rds/min; muzzle velocity 920 ft/sec, 280 m/sec.
The “Tommy Gun” was issued to the 1st Battalion of the 48th Highlanders in 1943 prior to going to Sicily. Brigadier General John Tagliaferro Thompson, a US Army Ordinance officer, was interested in developing an automatic rifle. He rejected all the conventional operating systems available at that time and chose a system developed by a Commander Blish, USN. Together they found that the Blish Lock would not work with high powered rifle ammunition but worked well with low powered .45 cal Auto pistol ammunition. Thompson was inspired and changed his design to a hand-held machine gun which he called the “Trench Sweeper”. The first models were produced in 1921 with the parts being made by the Colt company and assembled by the Auto-Ordinance company, a partnership of Thompson, Blish and a financier named Thomas Ryan, and was promoted as a Police weapon. In 1939 the French and British governments ordered more than 130,000 of them and the manufacture was taken over by the Savage company. They were not happy with the Blish Lock and wanted to change to a simple blow-back operating system because it was cheaper and easier to make. Auto-Ordinance did not want to change so Savage threatened to produce a competitive gun with the change and Auto-Ordinance acceded to their demand.