Ian calls this thing “American’s Vietnam 9mm SMG,” and that’s pretty cool. It’s a Smith & Wesson Model 76, which was basically a modified copy of the “Swedish K” M/45B.
This model has gained a bad rap, mainly due to being knocked off poorly, but the original guns were pretty nice. The rundown of features is enjoyable, and I’d really like to get my hands on one of those and burn up a bunch of someone else’s ammo in it.
The receiver is a round tube in which the bolt travels, and unlike most others of its kind, it has longitudinal grooves cut into it. They sorta look like rifling, but of course they are not cut in a spiral. This cool design feature reduces friction between the bolt and receiver, while also providing a place for fouling, dirt, and other crud to go, rather than allowing it to gum up the works.
If you like this thing, act quickly — it’s being sold at auction TODAY.