wcwarren Posted November 21, 2022 Report Share Posted November 21, 2022 I have a 1942 M-1. Was looking at getting an extra bolt for it. Just wanted to make sure that a M-1 bolt and a M1A1 bolt are interchangeable. William Link to comment Share on other sites More sharing options...
StrangeRanger Posted November 21, 2022 Report Share Posted November 21, 2022 They are completely interchangeable Link to comment Share on other sites More sharing options...
wcwarren Posted November 21, 2022 Author Report Share Posted November 21, 2022 Does it matter if the firing pin is fixed or floating? From what I have read it don’t. Link to comment Share on other sites More sharing options...
StrangeRanger Posted November 21, 2022 Report Share Posted November 21, 2022 M1 = floating M1A1 = fixed But either bolt will work in either gun, the receivers are identical. Personally, I strongly prefer the M1 bolt because it prevents the (admittedly rare) possibility of an out-of-battery discharge Link to comment Share on other sites More sharing options...
Merry Ploughboy Posted November 21, 2022 Report Share Posted November 21, 2022 48 minutes ago, wcwarren said: Does it matter if the firing pin is fixed or floating? From what I have read it don’t. The rate of fire is generally found to be higher (and I hesitate to characterize the difference) with the M1 bolt than the M1A1 bolt. See, for example:M1 VS M1A1 THOMPSON SUBMACHINE GUN CYCLIC RATE - Small Arms Review I believe that this is due to the operation of the M1A1 bolt includes advanced primer ignition that gives the shell casing an earlier rearward motion (thus slowing down the bolt sooner) than does the M1 bolt. MHO, YMMV, etc. Be well. MP Link to comment Share on other sites More sharing options...
reconbob Posted November 21, 2022 Report Share Posted November 21, 2022 Yes, back in the day Jim C. did rate of fire tests. M1 rate of fire 788 rpm, M1A1 641 rpm with military ball ammo. Bob Link to comment Share on other sites More sharing options...
wcwarren Posted November 21, 2022 Author Report Share Posted November 21, 2022 (edited) How can you tell the difference between a fixed and floating bolt. I actually don’t know what types in my Thompson now. Edited November 21, 2022 by wcwarren Link to comment Share on other sites More sharing options...
StrangeRanger Posted November 21, 2022 Report Share Posted November 21, 2022 On the floating pin M1 bolt the firing pin is not visible with the bolt cocked. The bolt has a transverse hole near the bottom front of the square section of the bolt body through which the pivot shaft for the hammer passes. There is a slot in the center of the bottom front of the square section in which the hammer rides. To remove the bolt handle it is necessary to push the protruding tip of the hammer rearwards which also moves the firing pin forwards ans into view in the bolt face. The M1A1 has none of these features and the firing pin is visible at all times Link to comment Share on other sites More sharing options...
wcwarren Posted November 21, 2022 Author Report Share Posted November 21, 2022 I just checked. My M-1 has the M-1 bolt in it. Link to comment Share on other sites More sharing options...
StrangeRanger Posted November 21, 2022 Report Share Posted November 21, 2022 From a safety standpoint that's a good thing Link to comment Share on other sites More sharing options...
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