Seems like plenty of M1/M2 carbines are available under $20k

MP40 is the best one I’ve shot.

Or the Glock with the fun switch.

I'd get a M3A1 grease gun. I shot one while in the Army and loved it. I carried a pig (M60C) for 7 years and loved shooting it too but the grease gun is just plain fun and easy to shoot well. Plus who red blooded American doesn't like the 45ACP round?

When looking at buying a MG today, you must looks at parts availability. IF you are going to shoot it. If you buy it and shoot it 1-2 times a year for a few mags, maybe take the risk.

Because of import parts bans and many of these guns may not have been made for 40 -80+ years parts are a huge issue. FNC, Grease Gun, Smith 76, MK760, MP40, Sterling, etc are all great guns, but parts are a huge issue. Do you want a $25K machine gun down because you can't get an extractor? I know people that bought a "spare" FNC semi just to have spare parts for their MG. That's a $4-6K investment for parts. People with Smith 76's can't get extractors so they don't shoot them. There is a guy that makes a run every 1-2 years and they sell out immediately. If you miss the run, oh well.

Think about bolts, extractors, trigger/sear parts, and barrels. What if you get a squib in a barrel? In a MG, you will end up with more than 1 stuck bullet if shooting full auto. It happens, even with factory ammo. I have seen several.

Look for guns you like but also has parts available, then STOCK UP!!! It's only going to get worse for parts. Even UZI parts are starting to dry up, extractors are going for $70+ and there are some JUNK extractors on the market. There are now some 3rd party UZI barrels bring made and some of them are junk also. UZI parts kits that use to be $200 are now $500-800 with no barrels (mostly). IE the barrel import ban.

Also think about magazines. UZI mags are still relatively available and not too expensive. $25-35 for 32 rnd IMI if you look. Sterling mags that use to be $20-25 are now $75 in poor shape if you can find any, same with Smith 76, MK760, MP40. Many people modify Swedish K mags to run in Smith 76/MK760 but that is work and some work, some don't. Grease guns mags are readily available because they were US manufacture. There are tons still floating around NIW but they have gone from $12-15 to $40-50 each.

I am not saying buy an UZI, just using it to compare parts price and availability. I have had all the above and like them all. But if I can't get parts to work on it or keep it running when something breaks, I don't want it.

Some version of a ma deuce (probably couldn't find one or at that price) but never-the-less a FUN choice. Mounted with a star light scope on top. Excellent sniper weapon. A buddy of mine used to fire quad 50s mounted in the back of a five ton truck.

I used an M60 a lot and also an M14 a few times. After firing these three I think you just become spoiled about which fully auto you like to shoot the most. The M16 was a full auto but no where near as fun as the other three.

Very sound advice.