AR Muzzle Brake

slimjim · Posted: Wed Jan 13, 2010 9:02 pm Post subject: AR Muzzle Brake

I've been enjoying shooting my AR-15 at Carbine matches. I've been shooting pretty accurately but my follow-up shots aren't as quick as I would like them. I was looking at some military photos the other day and noticed that the Army uses muzzle brakes.

So I decided that I should investigate if a muzzle brake could help speed up my follow-up shots. I procured one from Smith Enterprises

Some of the muzzle brakes on the market can get pretty pricey and some of pain inflictors integrated into the front. I choice this one because it has a single purpose, reduce muzzle disruption, just like the big guns. It also cost only $60 including postage.

slimjim · Posted: Wed Jan 13, 2010 9:26 pm Post subject: Re: AR Muzzle Brake

I've been pondering how to quantify the effectiveness of the muzzle brake. I want to go with more than it just "feels" better. I've been thinking of using a large cardboard sheet at about 25 yards and doing an off-hand double tap as fast as I can pull the trigger. The first shoot should be on target. The dispersion or distance away the second shots are from the point of aim should provide a measurable indication of how effective the muzzle brake is doing its job. I was going to do this with a bare barrel, the standard muzzle flash suppressor, and the muzzle brake. I will also check slow-fire accuracy for each configuration with different ammo. What do you think?

Pumpkinslinger · Posted: Wed Jan 13, 2010 10:17 pm Post subject: Re: AR Muzzle Brake

Use a shot timer to see if you can get back on target faster.

slimjim · Posted: Thu Jan 14, 2010 8:09 am Post subject: Re: AR Muzzle Brake

That would be good. I'll have to see if I can borrow one or maybe rig up a stop watch that will be reasonably accurate.

chambered221 · Posted: Thu Jan 14, 2010 6:50 pm Post subject: Re: AR Muzzle Brake

+1 on the shot timer !!!
One that records individual shot times and splits would be the way to go, that way you can calculate shot intervals.

I'd set up four 8" pieces of cardboard at 25 yards and double tap them at least 3 times to get an average with and without the brake.

As for muzzle breaks in general, they tend to work their best with the higher pressure stuff. Light loads may not show a noticeable difference.

slimjim · Posted: Thu Jan 14, 2010 7:18 pm Post subject: Re: AR Muzzle Brake

chambered221 wrote:

One that records individual shot times and splits would be the way to go, ...

Yes, that would be the way to go. Got to see if I can borrow one locally.

Vince · Posted: Fri Jan 15, 2010 12:31 am Post subject: Re: AR Muzzle Brake

The PACT Timer should do the job nicely for ya Slim.

Cheers, Vince

slimjim · Posted: Wed Jan 20, 2010 8:13 pm Post subject: Re: AR Muzzle Brake

Secured a shot timer from a buddy. Old but should work. May use my cellphone and call my answering machine and record the string, then time it when I get home if I have trouble with the timer. Should get out to try it on Friday.

slimjim · Posted: Fri Jan 22, 2010 6:11 pm Post subject: Re: AR Muzzle Brake

Got to the range today. Ran into 3 issues. I didn't bring the right tools to change out the standard flash suppressor for the muzzle brake. Needed more than just the wrenches. I've got to secure the rifle in some sort of clamping system. Everybodies shots were being picked up the the shot timer, even on the other side of the range. And the wind was gusting at 20 mph. The wind would push you around off-hand just as much is not more than any recoil. I did get get others on the range to pause and did some trial runs. So all I have to report today is my average shot interval in the gusty wind with the AR - 22LR was 0.77 seconds and the AR-.223 with the standard flash suppressor was 1.65 seconds. Not sure when I'll get back out to the range so it may be a week or two before I report back.

slimjim · Posted: Sun Jan 31, 2010 9:05 pm Post subject: Re: AR Muzzle Brake

What a beautiful day to be shooting. Overcast. Ice was covering the trees and bushes with a glaze of white. The roads were dry. Temperature did rise above freezing. The shooting tables were covered in ice but the wind was light. Bundled up with a double layer of long underwear to stayed warm. Shot for 4 hours and loved every minute.

The shot timer worked great and was definitely the ticket for measuring performance differences. I used a 6-inch bullseye at 25 yards and rapid fired a 10-shot string. Follow-up shots occurred every time the sight went back into the bullseye. The 10-shot strings provided 9 intervals to average. Without the wind buffeting your body like last time, follow-up shots were much closer in time. The 22LR time interval came way down to 0.33 seconds. Recoil is so low, you basically could pull the trigger as fast as you could. The mil-std muzzle flash suppressor interval was 0.91 seconds. I then removed the suppressor and shot a bare barrel, the time interval was 0.85 seconds – statistically the same. Then I installed the muzzle brake, the interval time came down to 0.73 seconds. Basically a 0.2 second reduction, rounds off to a 25% improvement. If I threw out the high and low time in each string, these improvement numbers remained the same. I also noticed the time interval was much more consistent with the muzzle brake.

You definitely could feel the reduction in recoil. Noise did go up but not objectionably and no where near as load as my .270. It felt faster than what I recorded. However, the timer doesn’t work on perception and was glad I quantified the results.

I also fired each configuration at 100 yards to determine accuracy and point of impact (POI) affects. I used 55gr FMJ from 3 different manufactures. There were some interesting results. I’ll post them when I get that data crunched including some pictures.

chambered221 · Posted: Mon Feb 01, 2010 6:31 pm Post subject: Re: AR Muzzle Brake

Now start working with different powders and find what makes that brake really work to your advantage !!!
I'm betting you can lower your interval times even more !!!

slimjim · Posted: Mon Feb 01, 2010 8:32 pm Post subject: Re: AR Muzzle Brake

Below is a composite of all the 5-shot groups I fired to determine the accuracy affects from changing the mass attached to the end of the barrel. I have experienced significant and dramatic changes in accuracy when I added a muzzle brake to my Mini-14. This was no exception but not as dramatic as on the Mini-14. The first row was Federal 55gr FMJ, 2nd is PMC 55gr FMJ, and the 3rd is Remington 55gr FMJ. The first column is with the mil-std flash suppressor that came on my S&W M&P-15 (16" barrel). The accuracy was not as good as it has been in prior sessions but this was the coldest I've shot this AR, about 33F. The second column is accuracy with the flash suppressor removed. The third is with the muzzle brake installed with the supplied lock nut. I knew the location of the mass would affect accuracy so I tried installing the muzzle brake with a crush washer which would move the muzzle brake mass further onto the barrel, similar to how the BOSS works. The results are in the fourth column.

I was not happy with how the POI shifted to the right and how the groups spread out using the crush washer. So I removed and reinstalled the muzzle brake with the lock-nut and lock-tite. I used more torque this time and was very pleased to see with the results which are in the 5th column (was out of PMC by then). The results were better than the previous install with the lock-nut, however, I believe in leaving well enough alone and seeing 5-shot group sizes just over an inch was good enough for me. This muzzle brake will stay installed for a while. I continued to fire at 50 yards and at 250 yards. The groups stayed consistent.

Here is a picture of the installed muzzle brake.

slimjim · Posted: Mon Feb 01, 2010 8:37 pm Post subject: Re: AR Muzzle Brake

chambered221 wrote:

Now start working with different powders and find what makes that brake really work to your advantage

Unfortunately, I don't have a reloading press set-up so can't reload with full-sized cases. I just use a Lee Classic Reloader that neck sizes. I just shoot bulk ammo in my AR for now except for reloading a few hunting rounds in new cases. I may get some hotter ammo and give the timing another try. I should also practice my body position and see if that makes any difference or I can improve my efficiency.

slimjim · Posted: Sat Feb 06, 2010 6:38 am Post subject: Re: AR Muzzle Brake

Going to pick-up some 40gr and 69gr at Cabela's today and will see how the brake works with different bullet weights.

chambered221 · Posted: Sat Feb 06, 2010 6:35 pm Post subject: Re: AR Muzzle Brake

Try some 5.56 NATO rounds !!! (as long as they're safe in your gun)