APEXgunparts Posted January 14, 2019 Report Share Posted January 14, 2019 Is their any difference between the late model Thompson 1928 barrel that lacked the cooling finns and compensator and the barrels that are fitted to the M1 and M1A1 models? Richard Link to comment Share on other sites More sharing options...
gijive Posted January 14, 2019 Report Share Posted January 14, 2019 Is their any difference between the late model Thompson 1928 barrel that lacked the cooling finns and compensator and the barrels that are fitted to the M1 and M1A1 models? RichardAPEXgunparts, The only difference is that the "boss" on the front of the barrel was threaded for the compensator on the 1928 Model. The M1 series barrels weren't threaded. The sight on the M1 Thompsons is pinned without threading. Link to comment Share on other sites More sharing options...
APEXgunparts Posted January 15, 2019 Author Report Share Posted January 15, 2019 Is their any difference between the late model Thompson 1928 barrel that lacked the cooling finns and compensator and the barrels that are fitted to the M1 and M1A1 models? RichardAPEXgunparts, The only difference is that the "boss" on the front of the barrel was threaded for the compensator on the 1928 Model. The M1 series barrels weren't threaded. The sight on the M1 Thompsons is pinned without threading. Thank you for that explanation. I have a follow up question.Is this GMRB TMG-2 barrel (listed as 10.5" 1928 Thompson)http://www.gmriflebarrel.com/tmg-2-10-51928-thompson-sub-machine-gun-barrel-45acp/ A suitable replacement for the barrel on my (Savage Mfg.) M1A1 Thompson? Richard Link to comment Share on other sites More sharing options...
Bridgeport28A1 Posted January 15, 2019 Report Share Posted January 15, 2019 I personally would use a WW2 manufacture M1 barrel as a replacement on a Savage M1 Thompson. New Old Stock barrels or used M1 barrels are available in the marketplace. I assume APEX Gun Parts has sold off all of your USGI M1 barrels out of the APEX inventory to be considering using an aftermarket barrel manufacturer? Link to comment Share on other sites More sharing options...
APEXgunparts Posted January 15, 2019 Author Report Share Posted January 15, 2019 I personally would use a WW2 manufacture M1 barrel as a replacement on a Savage M1 Thompson. New Old Stock barrels or used M1 barrels are available in the marketplace. I assume APEX Gun Parts has sold off all of your USGI M1 barrels out of the APEX inventory to be considering using an aftermarket barrel manufacturer? I don't think we are done selling original Thompson barrels and parts.My gun was a de-wat, I like GMRB barrels and thought about picking one up (TMG-2) to keep as a spare while they are still available.I was just wanting to know for sure it will fit an M1A1. Richard Link to comment Share on other sites More sharing options...
Adg105200 Posted January 16, 2019 Report Share Posted January 16, 2019 Technically the steel on the ww2 barrels is a tougher/harder (not sure which term would best apply) steel for FA/sustained fire applications, not that you will ever get your barrel hot enough to notice the difference in degradation Andrew Link to comment Share on other sites More sharing options...
Joe H Posted January 16, 2019 Report Share Posted January 16, 2019 (edited) Richard, To answer your question, I built a M1 semi with a Phila. Ord. receiver (have a SBR tax stamp) using the TMR-2 barrel. The PO receiver is built to the same specs as the GI M1. All other barrel related parts are M1 GI. Barrel fit up perfectly looks and runs great. The green mountain barrel has the full auto chamber per the GI specs. Only difference I could tell between the Green mountain barrel and a M1 GI barrel is that the Green mountain barrel is button rifled, The GI barrels are cut rifling. The steel as best I can tell is pretty much the modern equivalent of the original barrels, pre-hardened 4140 alloy steel or something similar. Joe Edited January 16, 2019 by Joe H Link to comment Share on other sites More sharing options...
APEXgunparts Posted January 17, 2019 Author Report Share Posted January 17, 2019 Richard, To answer your question, I built a M1 semi with a Phila. Ord. receiver (have a SBR tax stamp) using the TMR-2 barrel. The PO receiver is built to the same specs as the GI M1. All other barrel related parts are M1 GI. Barrel fit up perfectly looks and runs great. The green mountain barrel has the full auto chamber per the GI specs. Only difference I could tell between the Green mountain barrel and a M1 GI barrel is that the Green mountain barrel is button rifled, The GI barrels are cut rifling. The steel as best I can tell is pretty much the modern equivalent of the original barrels, pre-hardened 4140 alloy steel or something similar. Joe Joe, thank you for sharing your experience with these GMRB Thompson barrels. Richard Link to comment Share on other sites More sharing options...
Eagle3 Posted January 17, 2019 Report Share Posted January 17, 2019 Good information. Thanks for sharing. Link to comment Share on other sites More sharing options...
Gaffshot Posted January 17, 2019 Report Share Posted January 17, 2019 I got the Green Mountain barrel unfinished and had it parked to match my M1. Looks and runs great. Where are the USGI M1 or M1A1 barrels? I could not find any when I was looking last spring. Link to comment Share on other sites More sharing options...
Adg105200 Posted January 18, 2019 Report Share Posted January 18, 2019 I got the Green Mountain barrel unfinished and had it parked to match my M1. Looks and runs great. Where are the USGI M1 or M1A1 barrels? I could not find any when I was looking last spring.I would try Philadelphia Ordnance (Reconbob), he usually has usgi barrels if you're still looking. Andrew Link to comment Share on other sites More sharing options...
Gaffshot Posted January 18, 2019 Report Share Posted January 18, 2019 $350 is pretty high Link to comment Share on other sites More sharing options...
DZelenka Posted January 18, 2019 Report Share Posted January 18, 2019 $350 is pretty highNot if it is the only one you can find. Link to comment Share on other sites More sharing options...
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