Object Title

Centrefire automatic submachine gun - Thompson M1

Centrefire automatic submachine gun - Thompson M1

Object Number



Gifted with the Pattern Room by the Ministry of Defence, August 2005.

Physical Description

An open-bolt blowback submachine gun. The muzzle has a reinforcing band pinned in place, incorporating the foresight blade. Barrel profile flares slightly towards the breech end, and the barrel has a wood handguard with two finger grooves and, on the underside, the forward sling attachment. Magazine attaches to the underside of the receiver in a rail on the front of the trigger group, with release catch being a lever on the left side with a knurled end. There is no provision for accepting drum magazines. Ejection port is on the top right of the receiver. Charging handle is cylindrical in a slot on the right side of the receiver. Left side of the trigger group has two rotating levers for fire selection, one being the safety and the other providing select-fire capability. Backsight is a fixed, bent tab aperture on top of the receiver with no protection. Slightly contoured wood pistol grip, and buttstock is wood with a steel buttplate. Back sling loop is on the underside of the buttstock. Black oxide finish.





BarrelLength10.5 in
BarrelLength267 mm
OverallLength31.89 in
OverallLength810 mm
OverallWeight4.88 kg
OverallWeight10.76 lbs


Serial Number 56224


.45 in

Inscriptions and Marks

Right side of receiver
Inspection mark
GEG in a circle
Left side of receiver
Left side of receiver


With the outbreak of the Second World War, the US government was in need of large quantities of submachine guns. The M1928A1 had already been adopted for British service at the outbreak of war in 1939, but was later replaced by the much more cost-effective Sten. The US military had similar concerns over the high unit cost of the Thompson and met with Auto-Ordnance to discuss simplifying the design, both to reduce costs and improve manufacturing speeds. Savage Arms, who had been producing the M1928A1 under contract from Auto-Ordnance, proposed a redesign in early 1942, which the US adopted as the M1.

The M1 removed John Blish's complicated mixed-metal locking system entirely, changing the Thompson to an all-steel blowback operating system with a heavier bolt to control rate of fire. This substantially reduced the machining time of the receiver and bolt in conjunction with the changing of the charging handle to a simple cylinder on the right side of the gun, as opposed to a separate actuator piece. Provision for drum magazines was removed, allowing for a slimmer profile, and the quick-remove button on the stock was deleted. The barrel cooling fins were also cut entirely from the design, and a simple handguard replaced the vertical foregrip as standard. Earlier M1 Thompsons had a very simple L-shaped tab for the backsight aperture, but later a protector with triangular 'wings' was added due to the sight's vulnerability.