Size of Exit Hole on Muzzle Brake

[lawofsavage]

Looking around for which muzzle brake I am going to get has led me to ask a question that I haven't been able to find an answer to. Would the ID of the brake not matching ID of the barrel affect accuracy?

I know a lot of brake manufacturers say their brake may need to be opened up. Obviously, you wouldn't want the brake to be smaller but what if it was designed for a .30 like the Fat Bastard Break and you put it on a 6.5 would the .264 barrel and .308 brake have a detrimental affect on accuracy?

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

It must have been a different manufacturer with a standard 30 cal opening APA states the FB's is 7mm. The question would stil be the same.

http://www.americanprecisionarms.com/products-page/muzzlebrakes/fat-bastard-brake/

It might be easier just to call them and get them to explain it to me.

 

[Rhys]

Re: Size of Exit Hole on Muzzle Brake

Larger is no problem. If taken large enough it may lose some effectiveness, but probably not snogged to notice. I generally go for. 015-.020 over bullet diameter.

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

So, if you were putting it on a .264 and the brake in question was .308 diameter, would it be more effective to go with a .284 diameter break?

edit: Assuming the break's are the same in every way other than ID.

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: Rhys</div><div class="ubbcode-body">Larger is no problem. If taken large enough it may lose some effectiveness, but probably not snogged to notice. I generally go for. 015-.020 over bullet diameter. </div></div>

Thanks, I am deciding which brake to get and did not know if this should play a factor into my decision or not. Specifically, choosing between the APA LB exit hole (.264) and FB exit hole (.284). I'm about to call them right now and see what they suggest. I have not decided on that particular one but just using it as an example.

I am also curious just from a physics perspective.

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

Also, another question that comes to mind, is it important to have a recessed crown on a brake for a precision rifle?

 

[Strangedays]

Re: Size of Exit Hole on Muzzle Brake

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: lawofsavage</div><div class="ubbcode-body">Also, another question that comes to mind, is it important to have a recessed crown on a brake for a precision rifle? </div></div>
I think it is always a good idea.

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

I would think so as well, I just noticed a lot of brakes don't have one and wondered why?

 

[sawman556]

Re: Size of Exit Hole on Muzzle Brake

You don't need a recessed crown on the brake. The brake ID needs to be bigger then the caliber you're shooting through it. The bullet shouldn't touch the brake.

 

[Redman797]

Re: Size of Exit Hole on Muzzle Brake

With the BO FTE brake. they recommend at least .20 over

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: moredots</div><div class="ubbcode-body">With the BO FTE brake. they recommend at least .20 over </div></div>

I just have never seen these issues discussed anywhere and was very curious about it.

That is good info from badger.

 

[sawman556]

Re: Size of Exit Hole on Muzzle Brake

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: moredots</div><div class="ubbcode-body">With the BO FTE brake. they recommend at least .20 over </div></div>

That's huge!!! You sure it's not .02???

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

Would it be overkill to put a FB on a 6.5?

 

[Rhys]

Re: Size of Exit Hole on Muzzle Brake

Certainly not needed. I have put a brake on every 6.5x47 I have built however. Just set it up threaded for a can from the beginning. I figure if it's already threaded may as well make use of it. As a bonus it sure makes spotting your own shots a piece of cake. In some instances when shooting at 300+ when conditions were right I have actually been able to see the glint on the base of the bullet as it went down range with the sun behind me.

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

As of now my I think that the badger fte will be best fit for me. Good solid performance wIthout lookIng rIdIculous and the main positive for me is that it is not timed and is the clamp on style so I never have to worry about it affecting accuracy and I can still take it on and off myself. Also it comes with a .22 hole so the gunsmith can open it to the appropriate size which in my case as per badger instructions would be .284.

With this brake on a 12lb 6.5 cm would it be possible to observe your bullet impact as close as 100 yd. from anyone experienced with a setup similar to this?

 

[Killer Spade 13]

Re: Size of Exit Hole on Muzzle Brake

> than the outside diameter of the bullet is preferable.

As to the specifications, I don't know. If you're shooting a bullet with an outside diameter of .308, then I would surmise that the inside diameter of the brake should be around .328 inches or so.

Just make sure that the OD of the bullet is less than the ID of the brake.

DOH!!!

 

[dannyryan007]

Re: Size of Exit Hole on Muzzle Brake

I'm no expert in the field, but it would seem to me that the diameter of the muzzle brake would have to be larger than the diameter of the barrel. If it were the same size, it would keep friction on the projectile. The purpose of the break is to release the gasses behind the bullet in such a manner that it relieves felt recoil and muzzle climb. This is also going to take pressure off of the bullet which would in turn slow the acceleration process. It seems to me that having a break with the same diameter as the barrel would in fact slow the bullet. Probably not significantly, but still... Please correct me if i'm wrong. Always love to learn.

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

This is a good question as well that I would be interested in learning from o physics perspective. Originally why I asked this question was the question of would it degrade accuracy if the muzzle brake diameter was much larger for example .328 diameter muzzle brake on a .264 diameter barrel. Thanks for all the people posting that the diameter of the muzzle brake needs to be larger than the barrel. I appreciate all of y'all looking out for my safety

but it was stated in the original question that obviously needs to be the case and is definitely not at all what this thread is about.

 

[sawman556]

Re: Size of Exit Hole on Muzzle Brake

I would not want to see what happens when you fire a .308 through a brake with a smaller diameter hole. Well maybe on YouTube!

 

[Rhys]

Re: Size of Exit Hole on Muzzle Brake

It sends the brake down range a ways. Had a customer who found out the hard way.

 

[kortik]

Re: Size of Exit Hole on Muzzle Brake

<div class="ubbcode-block"><div class="ubbcode-header">Originally Posted By: OT-Medic</div><div class="ubbcode-body">... This is also going to take pressure off of the bullet which would in turn slow the acceleration process....</div></div>

"Pressure on the bullet" effectively ends when bullet leaves the muzzle end. Brake is mounted outside the muzzle end. Therefore, brake can not affect acceleration of the bullet, which takes place i n the bore of the barrel. The purpose of the muzzle brake is to create "obstruction" to the stream of high pressure gas on exit from the muzzle end, reduce the volume of gas moving in the same direction as bullet goes, and sometimes, depending upon design of the muzzle brake, re-direct some of this gas to reduce felt recoil.

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

Still haven't ordered one yet what do y'all like better between the Sako clamp on and Badger FTE. Would it be a problem on the Sako if it's opened up to .30 already for a 6.5 CM. Other than that they look really similar other than on is two ports and the other has three and the thread size. I know TBAC can thread suppressors for M18x1 thread so I don't think that should be a problem.

 

[Bennybone]

Re: Size of Exit Hole on Muzzle Brake

Most overlook the other variable of brakes and how they effect accuracy.

The thread size, not sure what you have on your Grendel but based on the barrel's profile if you are thin in the muzzle it could cause some accuracy degradation vs the same caliber in a heavier profile.

For example.

I have a 6x45 barrel that came from the factory plain (non-threaded) with an 11 degree target crown. It shot very well but I found myself yearning for a brake, CUZ ITS AN AR

Anyhow because my barrel was a medium to heavy profile I could choose my thread pitch, most AR-15 run the 1/2 x 28 but I opted for the 5/8 x 24 while is usually for the 7.62 guns.

Also the brake I put on is for .30 cal, while I am shooting a .243 (6x45) size projectile.

After installation of the brake with the larger ID sized brake I saw no loss of accuracy or POI shifts.

YMMV,

BB

 

[lawofsavage]

Re: Size of Exit Hole on Muzzle Brake

Went with FTE very happy with purchase