Will a 1/2-28 brake be good for a unthreaded 5/8 muzzle.

Ok, I ordered and paid for the holland brake, which was 1/2x28 which was all that was available at the time. I was told that it could be made to fit my barrel by turning down my barrel and it wouldn't have any negative impact on anything. But I just called the store and it hadn't shipped yet so I asked to have a 5/8 Brake instead. But of course that one is not in stock and won't be available for a couple of weeks. So I'll wait a couple of weeks and get the 5/8 , better to be safe than sorry. This is turning out to be more than I thought:) . Thanks for all the help guys.
 
This is the response I got from the smith who is doing the work for me. For .308 we will not install a 1/2-28 brake as the minimum barrel wall thickness fall below the required safety parameters ( you'd only have .074 wall at the lowest point). There are cases where these are threaded on but they are relying on the muzzle rake for safety support. 1/2-28 are more suited for ar barrels. We recommend using minimum 5/8-24 or 5/8-28 for 30 cal. After I posted here and realized it was more of an issue than I thought , I emailed the smith and this was his response. So this is what I'll do.
 
This thread is a classic case of too little information at the start. You asked a simple question and got the answers as they applied to what you gave. But then along the way it turns out that you're working on a .30 caliber barrel where the stub on the end is 5/8 and the main body of the barrel is bigger. That all TOTALLY changes what the "right" answer should be.

As it happens tiraq and your smith have the right of it. The folks that wanted to sell you that 1/2 inch brake because they had it don't know diddly. As your smith said it would leave far too little metal between the roots of the thread and the bore. Little enough that durability could easily end up being an issue.
 
BCRider said:
This thread is a classic case of too little information at the start. You asked a simple question and got the answers as they applied to what you gave. But then along the way it turns out that you're working on a .30 caliber barrel where the stub on the end is 5/8 and the main body of the barrel is bigger. That all TOTALLY changes what the "right" answer should be.

As it happens tiraq and your smith have the right of it. The folks that wanted to sell you that 1/2 inch brake because they had it don't know diddly. As your smith said it would leave far too little metal between the roots of the thread and the bore. Little enough that durability could easily end up being an issue.
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No disrespect , but it was an ovious question , in the third post I did say 30 cal brake. Maybe I should have said 30 cal barrel also. And I don't see what difference the thickness of the actual barrel is? All that matters is the muzzle .? I thought the guy who sold it to me knew what he was talking about as on his website it say's he builds or sells Percision rifles . But it just didn't make sense to me so I posted the question on here . After the responses that I got from CGN,I then decided to email the Smith and ask him his opinion . Thanks to some of the replays on here , I'm not stuck with a $300 brake that would be useless to me.
 
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There was nothing wrong with the question. Just that the bore size would have been good to know in the first place. Size wise the idea of turning down and threading to 1/2 inch threads on a .30 caliber barrel would have set off a red light right away.

The point is that to help us help you it's good to include more information right off the bat. That was all.
 
Brianma65 said:
This is the response I got from the smith who is doing the work for me. For .308 we will not install a 1/2-28 brake as the minimum barrel wall thickness fall below the required safety parameters ( you'd only have .074 wall at the lowest point). There are cases where these are threaded on but they are relying on the muzzle rake for safety support. 1/2-28 are more suited for ar barrels. We recommend using minimum 5/8-24 or 5/8-28 for 30 cal. After I posted here and realized it was more of an issue than I thought , I emailed the smith and this was his response. So this is what I'll do.
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Finally you have talked to some one with a brain and a calculator. Just doing the numbers screams 5/8" break not 1/2'. Really turning the barrel down and threading it will end up way to thin to give the brake good support. Don't even care what caliber it is it makes no sense to not match dimension to dimension.
 
I have installed hundreds of brakes using a 1/2 x 28 on 30 caliber barrels with absolutely no problems. Most of those barrels were about .650 at the muzzle.

The next size up is 9/16 x 24 and I have done many of those for larger calibers with .650 muzzles.

The 5/8 x 24 size I use when the muzzles are large.

All are precision turned and threaded in a lathe with the bore dialed in and the bullet clearance bored while attached to the barrel.

It does not compute for me to thread a 5/8's barrel for a 5/8's thread... there is no shoulder for the brake to tighten up against.

thinbarrelbrake2-0.jpg
 
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I'm with Dennis on this. A 1/2x28 works fine on a 30. I have put brakes on 30's with a .550 muzzle; pretty much need to go with 1/2 inch threads on those. I use 32 TPI on 1/2 and 9/16 but it probably means next to nothing; 28 tpi would be fine. A 5/8" barrel with a 5/8 thread would have to seat the muzzle on a shoulder inside the brake. Workable I guess but I wouldn't like it.
 
The OP's barrel is a composite one, with a large diameter shoulder behind the reduced muzzle diameter. Shorten this portion and there would be a solid, large diameter shoulder for the brake to pull up against.
 
The shoulder is twice as thick as the cut down muzzle. I'm guessing some of that muzzle will need to be cut off. It's about 1 1/2 long as it sits now. I already cancelled the 1/2 brake and ordered the 5/8, just gonna take a little longer. Just as well anyway as the smith said he wouldn't install a 1/2 brake on my 30 cal barrel.
 
BCRider said:
There was nothing wrong with the question. Just that the bore size would have been good to know in the first place. Size wise the idea of turning down and threading to 1/2 inch threads on a .30 caliber barrel would have set off a red light right away.

The point is that to help us help you it's good to include more information right off the bat. That was all.
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I see what your saying,and you're right. I know I didn't say anything about the size until 3 posts in and wrongly assumed everyone would know it was a .308. I just thought that if my muzzle was 5/8 why buy a 1/2 brake. But I listened to the vendor and then decided to ask here. I should of asked here first:) . And , I've taken your advice before and it worked out well for me, and it is appriated.
 
There is 1/8 of an inch steel , around the muzzle . Removing 1/16 of an inch to accommodate a 1/2 threaded brake would leave very little steel left (50% less).
 
Brianma65 said:
There is 1/8 of an inch steel , around the muzzle . Removing 1/16 of an inch to accommodate a 1/2 threaded brake would leave very little steel left (50% less).
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So what? It may not handle being used as a pry bar as well as a bare barrel but there are hundreds of 30 caliber rifles using 1/2 inch x 28 brakes with no problems.

When a 1/2x28 brake is fitted to a 30 caliber barrel and tightened against a shoulder it will handle any hot load you want to put through it...

A shoulder of 25 thou is sufficient to line the brake up square but it requires a precision thread fit and I would prefer to Loctite it in place with such a small shoulder.
 
The shoulder on my barrel is .960 . I'm not saying which way is the right way as I have no experience with either. All I'm saying is 1/16 seems pretty thin especially once you cut the threads in it. At the end of the day , the gunsmith I chose has told me that he would not install a 1/2 brake. And as I have complete confidence in him I have to go with what he said. I'm sure the guy who sold me the first brake , knows his stuff as well as he sells only precision parts ( barrels,actions,triggers,etc). And he offers gunsmith work as well. So I'll chalk it up to gunsmith personal preference. And I've read your webpage before and am sure you know your stuff as well and I always appreciate your posts.
 
Well going to a larger size is certainly going to work out for you. With a shoulder of .960 to butt up to you could even thread 3/4 inch...

But no one out there has to be afraid of a 1/2x28 brake on a .30 caliber.
 
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