Muzzle Break Hole

[B R Shooter]

Seems there are two schools of thought on boring the hole, when making your own. Once threaded and fit to the barrel, one way is to bore the inside of the brake the same size as the thread major diameter up to the end (making a chamber or sorts) and then bore the exit hole .020" over bullet diameter. The other way is to bore the entire length .020" over bullet.

I've done the chamber type quite a bit, have no complaints, but I have another in the works and thinking about trying it that way. Of course I can do the small hole type and try it, and bore it out later if need be, but rather do it once.

Opinions?

[waksupi]

https://www.sportsrec.com/make-muzzle-brake-5027118.html

http://www.the-long-family.com/making_a_muzzle_brake.htm

[B R Shooter]

I've seen the Long family site before, they are showing a large bore up to the first port, then .020 over bullet.

[John Taylor]

When I started making brakes over 20 years ago I made a brake tester to see what was effective. Some of the brakes on the market did not have much effect when tested on a 308 with 22" barrel. I ended up with a brake that was 2.2" overall length, 3/4" diameter, 42 holes at 90 degrees to the bore and a chamber at miner thread diameter with the exit hole at .020" over bullet diameter. This gave 50% reduction in recoil. Slanting the holes back did not improve the reduction in recoil but slanting them forward made for a quieter brake with only 25% reduction. When I was testing brakes I did not test one that was bored through at .020" over bullet diameter. Several gun shops like the brake turned down to barrel diameter but this does not make for good redirection of gas, the wall thickness need to be enough to do the job. When testing I found that 24 holes 3/16" diameter did just as well as 42 on the 308. Slits like Magnaport may keep the barrel from jumping up but don't do as well as a port that redirects the gas and stops the rocket effect. I have done quite a few revolvers with ports on both sides of the front sight using a carbide end mill and they work great.

[B R Shooter]

and a chamber at miner thread diameter

John, thanks for the reply. I believe we are talking the same thing, but to be sure, I was speaking of major diameter of the threads IN the brake, I believe you are speaking of minor diameter of the barrel threads. Am I correct?

[John Taylor]

John, thanks for the reply. I believe we are talking the same thing, but to be sure, I was speaking of major diameter of the threads IN the brake, I believe you are speaking of minor diameter of the barrel threads. Am I correct?

Bore the brake with the proper size for threading with a tap, miner diameter. Major diameter would be the OD of the threads.

[B R Shooter]

The same thing......one inside thread one outside thread. I single point thread the brake threads. No tap.