M3 Grease Gun vs Thompson Submachine Gun

1942–1945

1921–Present

Over 680,000

~1,500,000 units (World War II peak production) and limited post‑war runs

757mm (29.8 in) stock extended / 579mm (22.8 in) stock folded

762 mm (30.0 in) with stock extended; 660 mm (26.0 in) with stock folded (M1A1)

203mm (8.0 in)

254 mm (10.0 in) standard; 305 mm (12.0 in) for some export models

3,700g (8.15 lb) empty

4.4 kg (9.7 lb) empty (M1); 3.9 kg (8.6 lb) empty (M1A1)

30 rounds

20‑round box, 30‑round box, 50‑round drum, 100‑round drum (rare)

Blowback, open bolt

Simple blow‑back, open‑bolt, selective‑fire; rate of fire 600–1,250 rpm depending on model

Selective fire (semi/full auto)

Two‑stage trigger: semi‑automatic (first pull) and fully‑automatic (second pull) on early models; later models use a single‑stage full‑auto trigger with a selector switch

Fixed blade front, flip-up L-type rear (100 and 200 yards)

Rotary drum rear sight with 50, 100, 200, 300 yard settings; hooded front post; optional adjustable rear sight on later police variants