Originally Posted by JTJ
I have always wondered why they did not make a 45ACP carbine instead of adding another round to the supply mix. A lot of grease guns were issued later on but they were short barreled. A 16" or 18" carbine would have been nasty weapon. They could have also made a rimless 357 mag. Now that would be interesting. I would like to see a 9mm round on the on the AR platform. I am talking about the same length as the 5.45 round not a Luger.
i think it was weight issue and construction issue. the thompson m1 is a really heavy gun that takes a lot of intricate machining, direct blowback tend to be heavy. they wanted a lightweight carbine that was easy to produce with few parts. if you look at the carbine its either blocky parts or circular parts neither of which take many machine passes to create. the cartridge was designed to be low powered as to not stress the gun and be light to carry.
for the intended use it wasnt going to be used very much so supply wasnt that much of a concern at the time. the ammo was lighter round for round so shipping was easier than tossing in more 45acp. the thinking of the time was different than logistic theory today.
our supply lines were super efficient compaired to german russian or japanese.
thats my thoughts on it but im prolly not right.