Muzzle brake opening?

[MachV]

With Joel Russo's help I got the 308 Baer loaded and out for a little shooting. It deffinatly kicks less than my old Ruger 7mag but still more than my beat up old shoulder likes!
While cleaning it I noticed the hole in the brake seamed to be a little big. Just out of curiosity I grabbed a dummy 375/50BMG round and it fit in the opening of the brake.
How big should the opening be for a 30 cal? Does it make much of a difference?

 

[screech]

i try and keep mine within 30 thousandths. so the max mine would be on a .308+.030=.338. thats just me personally though.

 

[specweldtom]

Mach V, I've seen .020" clearance on the radius, or .040" on the diameter. That would make the exit hole .348" internal diameter. Screech has the right idea, though. .338" on the diameter should make the brake more effective. .375"+ sounds too big for a .30 cal, and if I understand brakes, would make it less effective, but might improve accuracy for that particular rifle. Minor changes in muzzle geometry or mass can make major changes in accuracy.

I don't like brakes, but have 2 rifles that have them. One is a custom, the other is a factory brake. The custom .338 cal exit hole is .378". The factory .458 cal exit hole is .500".

Beautiful rifle!

Just had a thought; maybe the brake was sized for a .338 cal.

Good shooting, Tom

 

[Black Diamond 408]

.020 - .030 is pretty much standard

 

[MachV]

I can shoot it the way it is but it would be a whole lot more fun with less kick. Noise and cosmetics are not factors.
So is less more? Would it be worth it to redo the brake?

 

[Black Diamond 408]

I would want the brake as close to tolerance as i could to get the maximum performance.

 

[woods]

.355" on a 338RUM

 

[specweldtom]

Woods, I really like the design of your brake. I make the clearance .0085" on the radius. Very tight. Have you had a chance to shoot it? It looks unfired in the pic.

MachV, the .458 cal that I mentioned is a .460 Wby with the Pendleton brake. In my opinion the integral brakes are much neater than the screw-ons, but they don't reduce recoil as much as a multi-chambered screw-on. From the replies you have gotten, it sounds like you need a much tighter exit hole to reduce felt recoil.

Good shooting, Tom

 

[woods]

Just broke it in yesterday with medium load of 83.5 gr IMR4350 behind 200 gr Accubonds and 210 gr Partitions. The brake worked really well. There was no blowback or pressure wave back in my face. The benches at the range at American Shooting Centers have 2 connected and separated by a plywood wall and each pair is separated from the next down the line by about 10'. I received no complaints or mean looks even when one fella was standing about 6' away talking to his buddy shooting at the bench, he never even looked around.

As far as effectiveness I will have to say something worked. In addition to the brake I installed 2 of the Edwards recoil suppressors in the stock, they are removable but help balance that heavy barrel. The barrel is a 26" #5 contour Brux barrel, so with the heavy barrel, the brake and the recoil suppressors it is not a light gun. That being said, the gun kicked somewhere between a standard weight 30-06 and a standard weight 300 win mag. I had something to gauge it with since I was also shooting an identical Beretta Mato 300 win mag.

As far as how it shoots, these are the last 2 strings

Now to load it up with some 225 gr TTSX's and RL22!

 

[Fiftydriver]

Bore diameter on muzzle brakes depends on several factors. In general, with a radial port muzzle brake like the one on your rifle, you will hear 30-40 thou over bullet diameter.

For a parition style brake you can go tighter, its recommended to still stay 20 thou over bullet diameter.

It all has to do with the material of the brake and the pressure level in the brake. A radial port brake holds pressure higher then and longer then a radial port brake simply because it can not dump the escaping muzzle gas as quickly as a partition style muzzle brake.

Because of this, its not a good idea to choke the bore diameter to tightly.

If I may offer a recommendation, if you really want to reduce felt recoil, you should switch to a partition style muzzle brake as they will far out perform any radial port brake at reducing felt recoil.

 

[Jeff In TX]

I had a badger brake put on my AR-15 to help eliminate muzzle jump. I felt the brake was totally ineffective as it really did nothing. I measured the diameter of the brake opening and it was .440 for my .223.

I questioned the gunsmith who installed the brake and he said the larger diameter wouldn't change anything in the amount of gases that would be vented off. I've been told by others well known smiths he's correct and I've also been told it would make the brake ineffective.

I do know when I changed the brake and I believe I'm 20 thou over, it made a huge improvement in reducing the muzzle jump.

Any thoughts?

 

[woods]

Fiftydriver, I must confess I am uneducated on the 2 types of muzzle brakes. What is the identifying characteristic that classifies a muzzle brake as one or the other?

When you posted "with a radial port muzzle brake like the one on your rifle", I didn't know if you were referring to the one I posted a picture of or the one shown in the original post.

Here is a pic of another type of muzzle brake that is on a 30-06 and it is .352"

It is not on my rifle but I was also shooting it this last weekend and noticed that it was louder and there was a puff of air that came back. It was effective though.

Jeff, I am no expert but it would make more sense to me that the tighter the brake the more effective it would be but probably not to a large degree.

 

[Hired Gun]

Okay,
Now you got to admit that is one very stylish modification to the end of a barrel. The way thy are cut it looks like it would be the loudest whistle in the world. My question, is it back bored at all or does the rifling extend through all that?

If the rifling goes through it, has it been tested to see if it spits jacket material?

I'm thinking it would work a lot better if the vents were bigger.

By the way, that would be a radial brake. A baffle or partition brake has partition walls with large holes to vent the gas sideways. A Holland QD brake is a partition brake.

 

[woods]

The one in the last picture is a detachable, they did such a good job with the joint and matching the blueing that it is all but undetectable. It is a Briley brake and more expensive than most but a little classier looking.

The first ports point a little forward and then the ports closer to the point a little backward, the theory being that the gases or ejecta would collide outside the barrel and mitigate blowback.