Will adding a muzzle brake always open up groups?

chrisward3

chrisward3

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Saw over on the hide that a guy using an AI AE MkIII with a surefire brake/supressor combo had groups open up on him with the following results:

w supressor: 0.4"
brake w/o supressor: 0.7"
w/o brake or supressor: 0.3"

Is this the rule or the exception?
 
My Nemesis is a better grouping rifle with the brake ( tested many time in the same conditions), not by much but enough to mentionned it... JP.
 
I recently added an SEI brake to my M305 and noticed that my groups had opened up. I have been assuming that the barrel harmonics have changed and that it is just a matter of finding the correct load again.

I'd be interested in hearing what others have found.
 
Adding something to the end of your barrel changes its harmonics and can re-tune your load. Sometimes that makes it shoot worse, sometimes better, sometimes it has no effect. You won't know until you try it. Some re-tweeking of the load may be required.
 
I just recently had the opertunity to shoot an AI rifle in .308 with a bolt on break and suppressor. We only had factory .308 ammunition with us and the rifle has had a larger number of rounds through it so I would expect a new rifle to shoot more accurately. How ever:

With just the bolt on break we were getting around 1"-1 1/2" groups.
With break and suppressor we were getting around a 1 1/2 - 2" groups at 10 but were seeing a POI of around 4" lower on paper. We didn't get a chance to shoot it with out the break on but I would suspect it would improve accuracy.

The one thing I felt was very interesting was the suppressor reduced felt recoil and muzzle rise, this allowing much faster target reacquiring. Compaired with out it where it required you to settle back on target and in to the rifle.

My educated guess would be that it all depends on the break, some will effect felt
recoil and accuracy more then others. I would think that is the break does not deal with gasses effectively there would be a turbulence present at the muzzle during the time the bullet passes through. As well, as mentioned before barrel harmonics could be effected by addition of a break. Positively or negatively.

Just my Observations.
 
Nobody would ever worry about changes that small except a BR shooter. And a BR shooter wouldn't be happy with .4" groups. You don't have a supressor either. However, a brake shouldn't alter group size.
 
sunray said:
Nobody would ever worry about changes that small except a BR shooter. And a BR shooter wouldn't be happy with .4" groups. You don't have a supressor either. However, a brake shouldn't alter group size.
Click to expand...

If in identical condition, i shoot 2 groups, one with the brake, one without the brake @ 100 metres, the POI is identical but from .25 i will go to .4-.5 MOA, i did that test maybe 5 times with the same results each time... JP.
 
If you are adding any chunk of metal to the end of your barrel it will affect the harmonics. If you have developed a load with a brake and remove it, it will affect the harmonics. How much it will change POI is anyone's guess.
 
Fitting a brake or a suppressor requires very precise threading concentric to the bore. A large percentage of brakes are poorly installed and less efficient because of this. If done well I doubt you will see a loss in accuracy with larger cartridges. Point of impact changes do occur compared to a bare barrel. Re-loaders may need to adjust loads to achieve the same accuracy because of the change of harmonics.
 
Simply quoting a couple of group sizes is worthless information. Group sizes need to averaged over a statistically significant number of samples in order to mean anything. I wouldn't read anything into the original info, especially when we are discussing only a few tenths of an inch difference.

In theory a brake or suppressor should increase accuracy as it will damp down muzzle oscillation frequency as well as help to strip gas off the base of the bullet. However, fitment and even port design and location can make a huge difference to the accuracy of any muzzle device. In the case of sound suppressors I can tell you that an asymmetric blast baffle can have a dramatic negative effect on accuracy. Most muzzle brakes utilize asymmetric porting because we don't want to direct gases downwards.
 
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