Gunsmithing Muzzle Break Threads

[Willys46]

Quick question, how much thread depth would you feel comfortable with in terms of a muzzle break. Here is a picture of the barrel I am thinking about adding a break to. The Flutes were cut long and only leave me with .400 worth of usable threading. It is on a 7 rem mag. The break I was going to use is 5/8-24 threading.

thanks
Willys46

 

[2156SMK]

Re: Muzzle Break Threads

I think you are asking about thread length, not thread depth as thread depth is how deep the individual threads are and is different for each thread pitch.

That being said, the general rule of thumb is that you WANT the same length as the major diameter so with 5/8-24 threads, you WANT 5/8" of thread length.

Now, I have seen VIAS brakes that were installed with only 1/4" of length on a 28 pitch thread and they stayed on the barrel just fine.

If you have 0.400" there to work with, cut the threads 3/8" long so the flutes don't look funky ending into the brake.

It's not the end of the world if the flutes actually DO end into the brake though and that would let you have a full 5/8" of thread length.

 

[sawman556]

Re: Muzzle Break Threads

Can it be cut back so you remove the ends of the flutes? Make a washer to go over the threads with the same size ID of the brake(like .0625 thick)? Recess the brake like .09375 to cover the washer/barrel seam? It would look like the flutes run into the brake instead of ending short. And make a thread protector as well?

I'm not a machinist so I'm not sure it could be done. Not sure I'd be comfy with only 1/4-3/8 of threads. Just a thought.

 

[ACK]

Re: Muzzle Break Threads

Barrel diameter? depth of flutes? If possible, turn the barrel to 5/8 diameter .75 deep, thread install brake (od s/b same as barrel), using a ball mill, blend in the flutes into the brake.

 

[JJones75]

Re: Muzzle Break Threads

Granted this is not close to optimal idea
but for just a light weight brake 6 threads would hold it on , I'd use some rockset to "glue" it.
with standard 60deg V threads with a class 3 fit the vast majority of the load is on the first 4 threads

24 TPI makes 6 threads at .250"

3/8" would work fine , again lock it in place

 

[Willys46]

Re: Muzzle Break Threads

Thanks for the advice guys. I actually have a little more than .4 just want to leave a little wiggle room.

OD of the barrel is .760

I just measured one of my thread protectors and it measured .440. And I actually have .429 before I hit the fluted. I think I will give it a go and see how it works out. The break will be turned to match the barrel conture.

 

[sawman556]

Re: Muzzle Break Threads

What brake are you going with?

 

[Willys46]

Re: Muzzle Break Threads

I have had great luck with the Straight Shot Gunsmithing "V" port Vaporizor breaks http://straightshotgunsmithing.com/

I have 4 of everything from 6-47 to 7 RUM and they work great!

"they even work well when you gunsmith puts them on upside down!". The reason I say that I had been shooting one on a 308 for months and shot a match where Nate Dagley the guy that makes the break was competing. He looked at it and sayed thanks for using my break but it's upside down! He busted my chops a little. Great guy and even better shooter!

 

[sawman556]

Re: Muzzle Break Threads

They look pretty good. I was unhappy with my APA so I have a PWS PRC on the way. I'll check those out if I'm not satisfied with the PWS.

 

[Roskoe]

Re: Muzzle Break Threads

I have put a bunch of muzzle brakes on guns with .400 of thread length. Shouldn't be a problem.

 

[athhud]

Re: Muzzle Break Threads

I've got the same issue with my 22/45. It will see suppressed use, so I figured I'd just cut a thread protector with flute ends milled into it. You could do the same, but rather than having a crown on the "thread protector", thread it all the way through. Thread something like 1-1/8" of the barrel, thread on your "thread protector", mill in the flute ends, then thread the brake on ahead of the "thread protector". Hopefully that makes sense.