Shoulder for muzzle brake on Mosin Nagant

[cm_machinist]

Hey guys,
I want to thread the end of my Mosin for a muzzle brake. The company that makes the muzzle brake suggests I talk to a gunsmith about how much of a shoulder will be left for the brake. The outside diameter of the barrel measures .587". If I get the barrel threaded to 9/16"-24 threads, the shoulder will only be about .012"-.013" wide. (I got that number by subtracting the major diameter of the threads from the O.D. of the barrel) How much of a shoulder do I need? Have you guys had muzzle brakes threaded on? Thanks for your help.

 

[gunrunner8]

If you insist on 9/16"-24tpi thread instead 1/2"-28tpi then .0075" shoulder is not enough. In that case your gunsmith need to cut the thread on barrel little longer than needed for the brake (say 3/8" longer) and machine 9/16"-24tpi threaded bushing 3/8" high and say 3/4" OD and locktite or soft solder it against that small barrel shoulder for positive brake headspacing.

 

[cm_machinist]

The 1/2" threaded muzzle brake that is made by the same company is meant for smaller calibre rifles. I wasn't sure if it was big enough for a 7.62x54r round. I could email them to ask.

 

[dogzilla]

You could have it threaded a little longer and use a jam nut and lockwasher

 

[cm_machinist]

That sounds like a good idea. That might be how the gunsmith will time the threads to ensure the brake goes on level.