Comments by "" (@neutronalchemist3241) on "The Iconic American WW2 Thompson: the M1A1" video.

  1. There are three possible reasons why the ROF slowed down when they adopted the fixed firing pin. 1) Rebound. In the previous model, when the cartridge was fired, and started pushing rearward, the bolt already rebounded vs the receiver and was slightly retreating, so the recoil found less resistance. 2) Advanced primer ignition. The fixed firing pin fired the primer when the cartridge was still seating, and so the bolt was still pushing forward due to inertia. So part of the recoil energy was used to stop the bolt. 3) The hammer spring. It was compressed when the bolt was pushed forward, so it aided the rearward movement.
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