Gunsmithing Minimum thread requirement for muzzle brake

[565fitter]

I just picked up a dta srs and wanted to have a brake made but was curious of the minimum o.d. the brake could be. It has 3/4" threads and the od of the barrel is .882". I'm sure that would be too thin to make the brake look seamless with the same o.d. as the barrel. How close can I get to that?

 

[NXS338]

I just picked up a dta srs and wanted to have a brake made but was curious of the minimum o.d. the brake could be. It has 3/4" threads and the od of the barrel is .882". I'm sure that would be too thin to make the brake look seamless with the same o.d. as the barrel. How close can I get to that?

What is the thread per inch? I would think you should be able to get it around 1in O.D, that would give you .125 wall thickness and only about .060 out past barrel. I make them out of 17-4 stainless hardened and it would be plenty strong.

 

[bohem]

It's not the thread root wall thickness you need to be concerned with, it's the net section left in the brake after you get contouring it. I've seen brakes that were cut so thin next to the baffles that the first 3 shots blew the end of the brake off.

 

[565fitter]

It's not the thread root wall thickness you need to be concerned with, it's the net section left in the brake after you get contouring it. I've seen brakes that were cut so thin next to the baffles that the first 3 shots blew the end of the brake off.

Yes thats what i am concerned about.

 

[bohem]

Unfortunately without seeing the brake geometry in detail and knowing the brake material as well as the spec sheet I am hard pressed to give you a thumbs up on it.

The brakes that I made for my stuff are a hardened SS and I provide other builders with minimum diameter requirements that are based on stress analysis and backed up by attempting to destroy one.

 

[NXS338]

It's not the thread root wall thickness you need to be concerned with, it's the net section left in the brake after you get contouring it. I've seen brakes that were cut so thin next to the baffles that the first 3 shots blew the end of the brake off.

That is correct, you cannot cut the metal so thin it will not give you the strength needed. This usually happens when people buy a brake made to a certain diameter and then it is turned down to what they want and you lose all of the metal in areas that make it strong. A brake should be designed with the size baffles that are properly sized to what the finished outside diameter of the brake is, accounting for this. the original question was how much thickness is needed outside of the threads to be strong enough and one of the factors for that is the size of the threads .750in in this case, which can have less wall thickness than say .500in threads. The baffle size and shape have to be determined after the O.D. is decided to make sure there is sufficient metal in all areas to prevent the failures you are referring to.

 

[biffj]

DT SRS has 3/4-24 threads so a thread depth of just over .054". The barrels are normally somewhere around .818 or so at the muzzle end if memory serves so you won't have enough material to hold the brake securely if you cut it to match the barrel. Just cut a taper from a reasonable dia like 1" stock to mate up with the shoulder on the barrel. The original 338 Brake was well over an inch in dia, worked well and looks good too.

Frank

 

[Sonic Crack]

Do yourself a favor and have a QUALIFIED smith install one of the already know good brakes. APA, Badger, ect.