If you’ve watched gangster films, you’ve seen a “Tommy gun”. A Tommy gun is officially known as the M1A1 Thompson submachine gun. It is called a submachine gun because it fires pistol cartridges rather than rifle cartridges. In most cases, a Tommy gun fired .45 caliber bullets, but could also handle 9mm bullets by changing the barrel and a few other parts. The advantage of a submachine gun is that it is smaller and lighter than a machine gun. Small enough to fit into a violin case:

The Tommy gun was used in World War II, but, since it was a war, there was a desire to lower the cost of the gun. That’s where the M3 “Grease gun” (so named for its shape similarities with a grease gun found in a garage for lubing a car chassis) came in. Where a Tommy gun was made with forged metal parts and wooden stock pieces, the Grease gun was made of stamped metal welded together. You can see the two guns in a side by side comparison here:

Here is a close-up view of the M3 shooting blanks:

Would you like to own a Tommy gun? Here’s an option – the Lego version

Thompson M1921 (working Tommy Gun)

See also:
- Weapons – How an AK-47 Works
- Public service announcement – even if a gun is loaded with blanks, it can still kill you

[[[Jump to previous BFTP - Blast from the Past – How Integrated Circuits (chips) Work]]]

If you would like to follow Brainstuff on Twitter or Facebook, here are the links:
- Follow Brainstuff on Facebook
- Follow Brainstuff on Twitter