THOMPSON VS MP 40

How do they compare for reliability? A friend of mine once attended a police demo where they fired an MP-40 (along with a lot of other weapons) and he noted that it had some significant reliability problems but that could have been ammo, care, or condition rather than the weapons design/construction.

 

Which Thompson are we talking? The really early ones (pre-war production, some overseas customers bought them from the US) use the "blish system of intermetallic cohesion" which is a system of sliding plates that operates on the principle of wishful thinking. One gunsmith I've talked to mentioned those plates getting mashed into the receiver.

I've mentioned before that I'm not too convinced by the stock and forearm retention system. The later thompsons were straight blowback, but it's still an extremely complicated design for an SMG.

In general I'd expect the MP40 to have the edge in reliability with the big caveat that the single-feed, two column magazine design has too much friction. Other SMGs sharing this design of magazine (STEN, M3) share a reputation for flaky magazine reliability. I have no earthly notion why HK reverted to the single feed, dual column design for the UMP series.

Fundamentally though, they're open-bolt blowback SMGs. They're both much simpler than say, a garand, and there's just not as much that can go wrong.

As for accuracy, they're freaking open-bolt SMGs. First shot accuracy is garbage on both of them as it is in any open-bolt SMG. I could nail man-sized targets at fifty-ish yards with the better portion of the ammo in the magazine. Greatly beyond that distance? Well, then you're hardly using the SMG correctly.

Recoil-wise the MP40 is a kitten. First person shooter video games that show MP40s climbing inexorably skywards are full of lies and slander. It's more of a gentle pitter-pat than a kick or even a jostle.

The Thompson isn't too bad either, but it lets you know you're shooting it. The stock sits extremely low relative to the bore axis, so there's more of a tendency for the muzzle to climb. Nothing a good weight forward stance and a firm grip can't cure within the weapon's effective range. Really, either weapon will put a stream of bullets on target if you mean to.

Fundamentally, the MP40 was a weapon of a later generation than the thompson. It was dramatically more suitable for mass production and had far fewer parts. The thompson was a first generation SMG; a peer to the MP-18. The MP40 was much more in line with designs like the Sten and M3. Really, the only reason the USA got away with using the thompson in WWII at all is because they had such overwhelmingly superior production capacity that they could reasonably produce such an extravagent, complicated design. Even then they simplified it and developed the m3.

 

I would go for the MP40.

The MP40 is lighter, which would have a huge effect on stamina as you wouldnt have to lug around a big ol' wooden brute. It has such little recoil that muzzle climb is virtually non-existent which would mean more rounds generally on target than having to stop firing to re-aquire the target, the collapsable stock means you can either have it extended for more precise shooting or have it collapsed making it more compact for room-to-room engagements.

The benefits about the Thompson is that it has a higher ROF and a more powerful cartridge. These and the fact that its mechanism means it has a higher recoil suggests that its an excellent CQC weapon, better than the MP40 in that role but the reason why i choose the MP40 is i would rather have the capacity to take shots from a (relatively) long range for an SMG and still have a weapon thats still quite useful in CQC compared to a heavy beast that chews through ammo and opposition faster than you can blink but its pretty much helpless at longer ranges