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M1 Thompson: Savage Simplifies the SMG (Ad-free)

The Thompson submachine gun struggled to find a market when it was originally produced, with the first batch of 15,000 Colt-made guns not finally all selling until the late 1930s. By that time, the clouds of war were gathering, and demand for submachine guns finally began to really grow. The US military had some Thompsons, and the British began buying as many as they could. The US wanted to increase production, and that meant simplifying the gun, both to reduce cost and to increase manufacturing efficiency. Talks to this end began in late 1941, and by February 1942 the engineers at Savage had a prototype of what would become the M1 Thompson.

This new version simplified almost every element of the gun, but most significantly it replaced the 3-piece Blish lock bolt with a solid one-piece affair that just worked as a normal blowback action. Unnecessary elements like the vertical front grip, Cutt’s compensator, quick-detach stock, and fancy contoured selector levers were discarded. The adjustable Lyman rear sight was replaced by a single metal tab with an aperture (quickly given a set of protective wings though, as the tab alone proved too fragile). The recoil guide rod was simplified, the oiling pads inside the receiver removed, and a simpler recoil buffer designed. The capability to use drum magazines was also discarded, and a new 30-round box magazine took their place.

The M1 was adopted in the spring of 1942, and July saw the first major delivery, of 48,000 guns. Simplifiecation work continued, however, and by the end of October a yet-simpler M1A1 pattern was adopted. This model replaced the hammer mechanism with a fixed firing pin. As a result, M1 production lasted only about 5 months. A total of 285,480 M1 Thompsons were made, but most of these were retrofitted to M1A1 configuration by simply swapping in the simpler new bolt. Finding intact M1 configuration guns is rather unusual today as a result.

M1 Thompson: Savage Simplifies the SMG (Ad-free)

Comments

Whilst the M1 version of the Tommy Gun was simpler and more practical than the M1921 and M1928…it didn’t look as classy and visually appealing IMHO (thanks to lack of the vertical foregrip and 50-round drum mag alike). Incidentally, I own an M1927 Thompson carbine (semiauto-only).

Christian D. Orr

In the late 1990s I got one of the Thompson parts kits out of the former Soviet Union. It only had the forward few inches of the (cut) receiver, so can't give markings, but it's mostly a 1928 style Thompson: cut for drum, Cutts compensator, Blish lock ... but no Lyman sight. Instead it had a simple L-shaped piece of metal, though with screw holes matching the holes for the Lyman. Dunno if it had a Lyman when sent to the USSR or not; it's possible the importer removed the Lyman sight for separate sale, and threw in a simple rear sight to make the kit complete?

Michael James Blum

No, it doesn't cause and particular problems. And there were a number of other SMGs before and after that used a similar system.

Forgotten Weapons

ok nobody else did that hammer thing and just went with fixed fireing pins. fine. but other than time, not too much material and cost I technically can't see that it would hurt any either. maybe that split hair safer?

Guido Schriewer

I think that one belonged to Front Sight in Nevada. I remember the RSO telling me how rare it was. It cost $40 a magazine to shoot it at lunch time.

Jeffrey Hartman

What was actually the point of replacing the bolts if it ran well even with the original bolts?

Aljosa Vidmar


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