MafiamanJ15 Posted April 7, 2019 Report Share Posted April 7, 2019 I've had a TM1 Thompson Carbine by Khar since 2016 and I only recently sent in a Form 1 to SBR it. The Form 1 is approved, but I still haven't gotten a barrel for it yet or figured out who I want to help with the barrel swap.I just had a quick question as to what barrels are compatible with it or which ones would be the best for an accurate Thompson M1A1 reproduction?I also thought I heard that Khar changed the threads on their barrels so that they will not work with USGI barrels.Is there a difference between a barrel for a semi-auto Thompson vs. a full-auto Thompson?Any help would be appreciated. Link to comment Share on other sites More sharing options...
95mustang Posted April 7, 2019 Report Share Posted April 7, 2019 My tm1 was usgi barrel threads.And a full auto barrel has a looser chamber....so fail to feed are a lot less frequent. I got my barrel from numrich and had very good luck. Link to comment Share on other sites More sharing options...
Hossbreed45 Posted April 7, 2019 Report Share Posted April 7, 2019 I'm doing the same to my TM1. Deerslayer can give you all the details you will need to SBR yours. He posts here frequently. Shoot him a PM... Link to comment Share on other sites More sharing options...
malibu12 Posted April 8, 2019 Report Share Posted April 8, 2019 I have the same questions , please post his reply when you talk to him . no reason to send him multiple messages with the same questions. Link to comment Share on other sites More sharing options...
Baltimoreed11754 Posted April 8, 2019 Report Share Posted April 8, 2019 (edited) I also have a question for the forum. Given the fact that the 18 in bbl on your Thompson will have to be removed anyway to install a ex military 10.5 in bbl why not have your long bbl cut to 10.5 and machined over buying another bbl? I would want my sbr build to keep the Cutts compensator. This is what Id build. Edited April 8, 2019 by Baltimoreed11754 Link to comment Share on other sites More sharing options...
MafiamanJ15 Posted April 8, 2019 Author Report Share Posted April 8, 2019 My tm1 was usgi barrel threads.And a full auto barrel has a looser chamber....so fail to feed are a lot less frequent. I got my barrel from numrich and had very good luck.Thanks for the info, I was looking at the barrels on Numrich originally, but I wasn't 100% sure if a "full-auto" barrel would work in a semi-auto carbine. Link to comment Share on other sites More sharing options...
Baltimoreed11754 Posted April 8, 2019 Report Share Posted April 8, 2019 Just looked at Numrich and they offer four 10.5 in Thompson bbls, two are threaded for the cutts and the other two for the slip on sight. On each pair one is listed full auto and the other not but the parts numbers are the same?? My guess is that the bbls are all relatively current manufactured SA bbls not FA bbls. Link to comment Share on other sites More sharing options...
Oldtrooper Posted April 9, 2019 Report Share Posted April 9, 2019 I also have a question for the forum. Given the fact that the 18 in bbl on your Thompson will have to be removed anyway to install a ex military 10.5 in bbl why not have your long bbl cut to 10.5 and machined over buying another bbl? I would want my sbr build to keep the Cutts compensator. This is what Id build.The contour of the 18 inch semi auto barrel is not correct for a Thompson SBR ... Technically speaking you can cut the barrel and fit a compensator to the cut down, but machining the barrel to the correct outter dimensions would be more costly that just buying a 10.5 inch version.... Plus your Cutts nor a sight ring would no longer fit the end of the barrel as without the swelled out end, the barrel would be too small in diameter for either to fit. Ultimately it would be a Frankengun ... I know ... I went that route and ended up having a correct barrel installed by deerslayer ... This is how it should look ... Link to comment Share on other sites More sharing options...
Baltimoreed11754 Posted April 9, 2019 Report Share Posted April 9, 2019 (edited) Oldtrooper, I like your build, hope mine turns out that sharp. This is how I did my cutts comp on my AR/Thompson. On a semi auto Thompson the cutts is, in reality only ornamental. It certainly worked on a full auto gun. I drilled out and threaded a cutts that came from Belgium which put the 18 inch Olympic Arms .45 bbl inside of it. Might be able to do the same thing on a cut down Thompson bbl? When my rifle gets here Ill get some measurements. Edited April 12, 2019 by Baltimoreed11754 Link to comment Share on other sites More sharing options...
Oldtrooper Posted April 9, 2019 Report Share Posted April 9, 2019 Oldtrooper, I like your build, hope mine turns out that sharp. This is how I did my cutts comp on my AR/Thompson. On a semi auto Thompson the cutts is, in reality only ornamental. It certainly worked on a full auto gun. I drilled out and threaded a cutts that came from Belgium which put the 18 inch Olympic Arms .45 bbl inside of it. Might be able to do the same thing on a cut down Thompson bbl? When my rifle gets here Ill get some measurements.You can fit a compensator over a cut down barrel, but the inner dimension of the cutt's will have to be expanded, which will make it unusable on a 10.5 inch barrel ... I found out the hard way and had to have deerslayer find me a replacement compensator when he did my rebarrel with the 10.5 inch barrel. To me it is worth having a good Thompson smith do the work, as while the barrel is off a lot of polishing that needs to be done is easier to do ... Plus it just looks better. Link to comment Share on other sites More sharing options...
deerslayer Posted April 11, 2019 Report Share Posted April 11, 2019 All barrel threads are the same.. But sometimes tolerances on kahr or aftermarket barrels need a tweak to screw in... I like thompsonbarrels.com 1 Link to comment Share on other sites More sharing options...
StooperZero Posted April 11, 2019 Report Share Posted April 11, 2019 unless you have the knowledge and some form of proper tools it can be hazardous to your guns health. I did my own SBR work, swapped out the stupid smooth barrel for a gi with the cutts on it that I got for $40. when the threads broke on the first barrel it sounded like a gunshot in my garage using my 4 foot cheater bar on my jig I made. Link to comment Share on other sites More sharing options...
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