Can muzzle brakes alter the barrel accuracy?

[mike06]

I shot 5 shot groups last night at 200 yds with and without the brake. I'm not the best shooter but in my opinion it grouped tighter without the brake installed. There is a really noticeable difference in the recoil without the brake so they clearly do work but at what expense? I'm sure there are way better brakes out there that have no affect on accuracy. I'm going to retest tonight at 300 yds.

On some of my other 308 rifles I have had to change my loads a little. As in powder amounts. My friend I shoot with has a AR15 and his shoots better without the flash hider.

 

[Ned Ludd]

A brake can have at least two different effects on precision. First, you're adding a weight to the barrel at the muzzle, which is the same thing a tuner does. The difference is that the brake is generally not quite as easily adjusted, whereas a tuner is specifically designed to allow you to readily adjust the tune. The addition of a muzzle break in this context might make groups smaller, have no noticeable effect, or even make them larger. If it makes the groups larger, you will simply have to adjust the load to tune it back in as best you can.

Second, it's possible that a brake that was improperly mounted or timed improperly could have some kind of undesirable blast-dependent effect on the bullet as it exited the bore. However, proper mounting/adjustment should alleviate those kind of issues. As with the effect of a brake on barrel harmonics, to a reasonable extent these type of effects should be tunable with proper load development. But the load development needs to be carried out with the brake installed. Installing the brake after load development, or taking it off after it was attached during load development, can easily lead to a noticeable change in precision.

I have had similar results using a MagnetoSpeed chronograph. Like a muzzle brake or tuner, the MS adds weight to the barrel at the muzzle, and it definitely has muzzle blast-dependent effects. With the MagnetoSpeed attached, groups sometimes seem unchanged, sometimes are larger, and sometimes are smaller. The effect largely depends on the specific load/rifle and where in the tune window it is.

 

[misser]

when I first installed a brake it was horrible . I was about to throw it out when I thought, what the heck maybe if I put it on the lathe I could fix it . and it worked, it went from 5inch group to 1/2 group

 

[tonyb]

Just remember when testing groups with and without the brake, if your load was developed with the brake on, it is an unfair comparison comparing it to a group with the brake off. Try developing a load with the brake off, and see what the group size does when the brake is reinstalled. Either way, the rifle needs to be tuned to the way it is shot.

Tony.

 

[varget204]

I have a APA Micro Bastard on my 6 Creedmoor,If i tighten much past hand tight,groups go from 1/2" or less to 1.5--2"

 

[tonyb]

I have a APA Micro Bastard on my 6 Creedmoor,If i tighten much past hand tight,groups go from 1/2" or less to 1.5--2"

Interesting!!!

Tony