Thompson, the original Thompson, will always be known for their submachine gun. The weapon is iconic and is known for being used by soldiers, gangsters, and G-Men. However, it was Thompson’s only weapon design. They produced several designs, including three .30 cal Thompsons. As a fan of obscure and old guns, I wanted to share these three oddities.
The Thompson Autorifle – The First of the .30 Cal Thompsons
The first of our .30 Thompsons doesn’t look anything like the submachine gun that the company would become known for. The Thompson Autorifle was an attempt to bring a semi-auto .30-06 to the United States Army. It competed with, and eventually lost to, the Garand.
The Thompson Autorifle was a semi-auto .30-06 that relied on the Blish lock. The Blish lock promised to deliver a delayed blowback experience that would be safe and comfortable. The idea of a friction lock created by two different metals and relying on velocity to increase friction turned out to be bunk. What we got was a direct blowback .30-06.
The end result was an extremely heavy recoiling rifle that was sending cases out so fast they reportedly embedded themselves in wood. I don’t imagine the rifle’s receivers had a very long lifespan. We know the bolts didn’t because one destroyed itself after 1,106 rounds.
Outside of the fact you could injure a guy with an ejecting casing, the rifle was also found to be too long, too heavy, and hard to take apart. The rifle required an oil pad to feed the cartridges smoothly to the chamber. The rifle fired from either a five-round magazine or a 20-round option was available.
Thompson Light Rifle – The Littlest of the .30 Cal Thompsons
The Thomspon Light Rifle uses the .30 Carbine cartridge, so it’s one of our .30 cal Thompsons, but it’s not a .30-06. This makes it the most practical of the .30 Cal Thompsons. When the U.S. went looking for a light carbine for noncombat troops, they ended up with the M1 Carbine, but it wasn’t the only gun trying to capture the contract.
There were roughly a dozen different entries, including this model from Thompson. The Thompson Light Rifle carries the same layout as the original Thompson, but some models ditch the wooden handguard for a metal skeletonized model, and some still have the wood handguard. Barrel lengths varied as well, and of course, the magazine changed.
Thompson attempted to modify the original design to save weight and reduce cost. This led to more metal handguards and simplistic features. The end result was a gun that weighed 5.5 pounds and used a recoil-operated locked breech. However, it was still too expensive and complicated.
The Other Thompson .30-06
The rarest of the .30 Cal Thompsons is a .30-06 rifle variant that looks like an actual Thompson. It looks like the creators stretched a standard Thompson SMG to fit a .30-06 cartridge and magazine. The gun did use BAR mags with an added oil pad. The extreme pressure of the operation required an oil pad and lubricated ammo.
Only one of these experimental Thompsons exists, and it was made in 1943. It appears to be the only one and is, or at least was, privately owned. An old VHS uploaded to YouTube shows the most we know about the gun. The presenter explains that it is a blowback-operated firearm and used a delayed blowback, but not the Blish lock.
From what I can understand from the video, it uses some form of plunger-delayed blowback system combined with a strongly tensioned recoil spring. The collector wisely will not fire it due to the fact no one’s sure what will happen if you do. Will it explode? Will someone be eating a recoil spring? It’s too valuable to risk.
The .30 Cal Thompsons
The Thompson SMG spread out of .45 ACP, more than people know, but it wasn’t very successful outside of .45 ACP. In fact, the Thompson company wasn’t superbly successful outside of the Thompson SMG in .45 ACP. However, they weaved an interesting history of prototypes and failures.
