Comments by "" (@neutronalchemist3241) on "Thompson SMG in 30 Carbine" video.

  1. The Thompson SMG is an heavy design in itself. The walls of the receiver are way thicker than what's necessary. That's why it weighted almost 2 lbs more than the grease gun.
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  2. Because a regular Thompson was heavier than a M1 rifle.
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  3. Mind that the .30 carbine originated from a family of cartridges developed for the Winchester 1905 and 1907 blowback carbines, and it was not the most powerful of them ( the .351 Winchester Self-Loading of the model 1907 was). The experiments done during the war determined that a 570gr bolt was enough to safely fire even proofloads, so it was entirely feasible to design a six pound rifle in .30 carbine using the blowback system (the Winchester model 1905 weighted 7lbs, and the model 1907 8lbs). The problem is that the Thompson SMG is an heavy design in itself. Unfortunately, if you want to make it select fire, the more practical way to slow down the ROF in a blowback design is to enhance the weight of the bolt (that's why WWII 9mm SMGs had bolts that weighted nearly 700gr, that were clearly an overkill only to fire the 9mm para safely).
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