Muzzle brake diameter and bullet turbulence

[RampedRaptor]

Hello,

Question: Does using a larger than required muzzle brake bore diameter have a negative impact on bullet flight?

The google search results I’ve obtained resulted in mostly threads about “will it work,” “recoil reduction loss” etc.

I’m curious about the possible negative impact on accuracy that using a 30 cal brake on a 6.5 caliber rifle could cause with regards to turbulence as the bullet exits the barrel/brake.


This pertains to shooting small groups (.1-.2s) at extended ranges and not PRS like disciplines.

Please restrain from the general comments of “get the right size brake,” “yeah it’ll work” and “it’ll have a little less reduction in recoil.”


Anyone have a link to a study that has already been conducted on the subject?

Thanks in advance for any guidance,
RR

 

[Uthink Uknow]

Because I shoot short range BR and muzzle brakes aren't allowed I can only answer with the terms you won't allow and so I will refrain.

 

[dttheliman]

Using a 6.5x47 locked in a rest with a cb30 brake on it (so 30cal brake) there was zero difference with or without the brake except with the brake it was easier to keep eyes on target after firing. No difference either with a 6.5 dedicated brake - now just keep the cb 30 on as I shoot suppressed with a dedicated 6.5 Ultra 9

 

[ireload2]

If you shoot enough you don't need a brake.
I only have one 8X57 rifle with a brake. The exit bore is much larger than 8mm yet the brake is very efficient.
I only shoot it when some bozo shows up at the range and takes the bench next to me with something like a braked .300 Weatherby. For some reason those guys don't mind the blast of their own rifles and inflicting it on everyone else. But they are the first to give me the evil eye and leave when I fire my braked rifle.Since the last time I did that to two guys my range outlawed brakes which is fine with me. Maybe your range will do the same if you shoot enough.

 

[Dusty Stevens]

Some brakes are more effective than others so a well designed brake even being the wrong caliber will help more than a poorly designed brake bored to the right caliber. Brakes with chambers before the exit and lots of surface area directing the gas back work better than just holes bored in a chunk of steel with a hole thru it for the bullet to exit like some ive seen.

 

[Milo 2.0]

Using a 6.5x47 locked in a rest with a cb30 brake on it (so 30cal brake) there was zero difference with or without the brake except with the brake it was easier to keep eyes on target after firing. No difference either with a 6.5 dedicated brake - now just keep the cb 30 on as I shoot suppressed with a dedicated 6.5 Ultra 9

Tbac brakes aren't what I'd ever choose to use stand alone. For any brake to work it has to be able to utilize gases coming from the barrel. I have a 419 self timing brake on my 7 saum, pretty sure 30 cal, it's a dream to shoot, recoil and staying put. If I put in on a 6xc, it would more or less be a noise maker.
Brakes have came a long ways in just 3 yrs, I think using software like silencer makers use will only make designs better.

 

[Bart B.]

A related issue with the first M14NM 7.62 NATO match rifles happened with their flash supressors.

Good handloads tested near half MOA at 600 yards in clear weather. When it rained, groups opened up near MOA.

Those supressors were reamed reamed out several thousandths to solve the problem. "A little drop'll do ya bad!" was a common phrase when the rains came. The lead engineer at TRW for the M14 production noted that rain drops and snow in the suppressor would destroy bullets.

 

[roadkill61]

OK can anybody answerer the original question. DOES A LARGER THAN NECSAARY HOLE UPSET THE BULLET LEAVING THE BARREL.

 

[M14AMU]

NO!

 

[seymour fish]

NO!

Have a megaphone deal made out of old washing machine parts, so have to agree

 

[LA50SHOOTER]

No and your not getting the benefit of the correct caliber brake. - Which maybe isn't a big deal to you.
I personally try to avoid muzzle breaks whenever possible even in larger caliber rifles, its one less thing that can be "suspect" as a cause of loss or lack of accuracy. - I shoot 50 caliber & it really isn't practical to "Not" have a brake especially on a light-class competition 50 BMG rifle. This being said, IF your going to have one a properly installed one & the exit & holes through the chambers should be correctly sized for the caliber. (If the brake is a chamber / multi-chamber type).

 

[ireload2]

If you are strictly concerned with accuracy, the variables due to powder type, charge weight, pressure and bullets would make an exact but general answer to your question impossible.
You can't even answer the question for all the variables without a brake.

 

[Zero333]

I shoot a 243win with a brake bored for .338" bullets. Works flawless. I had it on a 300winmag but the muzzle blast was way too much as to give me (the shooter !) migraines.

Here is a pic to show how the 243win shoots with that brake...

Those are 5-shot groups at 109 yards (100meters) trying different seating depths...




And here is the rifle...

 

[Dgd6mm]

OK can anybody answerer the original question. DOES A LARGER THAN NECSAARY HOLE UPSET THE BULLET LEAVING THE BARREL.

NO!

 

[LA50SHOOTER]

I shoot a 243win with a brake bored for .338" bullets. Works flawless. I had it on a 300winmag but the muzzle blast was way too much as to give me (the shooter !) migraines.

Here is a pic to show how the 243win shoots with that brake...

Those are 5-shot groups at 109 yards (100meters) trying different seating depths...

View attachment 1048053


And here is the rifle...

View attachment 1048054

- Interesting Indeed. - I'm not questioning your post at all. The targets speak for themselves. - By chance have you run a comparison test with No muzzle brake with the same load at the same range under similar range shooting conditions ??

I'm not claiming to be a "muzzle brake expert" I have taken the opportunity to read "The Accurate Muzzle Brake" by Troy Newlon. And depending on what gunsmiths you talk to the diameter that they are bored at varies, for example the Holland Quick Discharge brake in .338 caliber, the instructions tells the installer to ream it to 0.030 over bore diameter. - A couple of 50 caliber brake makers ream to 0.550 which is 0.040 over bore diameter.

- Ron -

 

[Uthink Uknow]

So you care to post the moving backer for those five shot groups?

 

[carlsbad]

an uncentered hole upsets a bullet. I always install the brake and then bore it concnetric with the rifle bore. As long as the 2 are concentric, I don't see the oversize hole upsetting the bullet. But if you have evidence that it is not working, then the brake is affecting the tune. that would be my guess. --Jerry

 

[Zero333]

- Interesting Indeed. - I'm not questioning your post at all. The targets speak for themselves. - By chance have you run a comparison test with No muzzle brake with the same load at the same range under similar range shooting conditions ??

I'm not claiming to be a "muzzle brake expert" I have taken the opportunity to read "The Accurate Muzzle Brake" by Troy Newlon. And depending on what gunsmiths you talk to the diameter that they are bored at varies, for example the Holland Quick Discharge brake in .338 caliber, the instructions tells the installer to ream it to 0.030 over bore diameter. - A couple of 50 caliber brake makers ream to 0.550 which is 0.040 over bore diameter.

- Ron -

I have run a test with and with out muzzle brake with a load that I developed with out the brake.
The groups with the brake averaged a little smaller. Five, 5-shot groups with and without.

 

[Delfuego]

Question: Does using a larger than required muzzle brake bore diameter have a negative impact on bullet flight?

Absolutely not. The added benefit is that you also have extra clearance for all the garbage that builds up on the inside of the brake. I will always run one size up now.

 

[Uthink Uknow]

Zero333,
That test proves little or nothing. Picture a rifle with a tuner that weighs 4 ounces. Moving that tuner just one fourth of a revolution moves the weight a minuscule amount. And that will affect group size enormously at 100 and 200 yards - heck, even more at greater distances. That tuner is on the barrel and so it's weight is much less than the weight of your brake out past the end of the barrel. If you are shooting groups like that all the time, don't change anything.
In the case of a .30BR, moving the weight one hour or one twelfth of a revolution will get you big changes in group size.