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Barrel Chop and Threading Difficulty

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Hey guys I am considering chopping my barrel down to the legal limit of 18.5" and rethreding using the thread alignment tool and threading die from CSS. Has anyone done this and it is anything more than DIY. I have done many conversions and consider myself pretty handy. I just dont wana get in over my head.





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legal limit is 18" but most people go 18.5" to be safe


after you measure it properly use a hack saw just make sure to score the barrel properly to make it a nice clean straight cut then use files to debur the end


In my experience, you have to lathe the bbl down to proper .O.D. and lathe down the front of the muzzel (per OEM), after shortening from 24" to 18" (and 19"-12.5". Every one I have done had to have O.D. reduced for proper threading.

Other's experiences may be different.


But....I have never chopped a 19 to 18 though, so the O.D. might be the same on that one (prolly is), I honestly don't know, and I ain't gonna check until I do one :lolol:

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I have done 2 19-18" cut, crown, and rethreads. It would have been much easier and faster if I could turn it on a lathe, but I did them both by hand. The OD was close enough to use a die for the threading. Go 1/8 turn with the die, back out 1 full turn every time, and be generous with the cutting fluid. If you go 1/4 turn on fine threads like this, the threads will not look cleanly cut. They will probably be fine, but will not look perfect upon close scrutiny. Removing the threads from the very end of the muzzle is a lot of work and you really need to have a good eye for things. You will pretty much file the outside of the barrel down until the threads are gone.


I went 18 1/16" on the second one. Bet your ass there was a lot of checking, rechecking, and checking the rechecking. Be sure that the bolt is absolutely all the way forward when checking. Why even bother if you are only going 18.5"? That is less than 1" on a 19" S12 and definitely not worth the effort. The 2 original barrels that I cut were 19 1/4" and 19 3/16" from the bolt face.



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