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Barrel Threading


Sep 17, 2008
I like to have at least a 0.050” wide registration shoulder on a barrel when threading for a suppressor. However I have several hunting rifles that are too small at the muzzle for a 5/8-24 thread and a registration shoulder. What are the thoughts on threading at 1/2-28? Largest caliber is 30 cal.
I've had no issues running a SiCo Hybrid 46 on a 1/2-28 threaded 7.62 AK. That thing has been quite abused in classes and matches. Haven't had an issue with the thread on a 30cal bore.
+1 on the idea of a shoulder-nut sort of thing to get the extra registration. A .308 hole in a thing with a minor diameter of 0.4575 only leaves you .073 of wall thickness, which seems like very little to survive any bending or rough handling.
1/2x28 is fine on 30 cals. I've threaded hundreds of barrels that way. 7mm mag, 300win mag, 30-06, all 1/2x28 with no problems.
I machine in place adapters upping the taking the threads from .5 to .625 with a bigger shoulder diameter to support the can.
God Bless,


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Moderators that rely on a spigot for alignment will allow you to keep your threads as close to barrel diameter as possible, your then aligning reference is on the spigot not the shoulder.