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View Full Version : Muzzle Brake Causing Short Cycling?


Bogart
02-22-2011, 8:40 AM
So I have a 20" AR-15 that will short cycle with the large muzzle brake I have on it. However, once I take it off the gun cycles properly. Is this common? Why would this happen (what physics are involved here)? I have confirmed that this is the case by using the same ammo and removing and installing the brake several times during a shooring session.

Thanks in advance for the info.

coltn46920
02-22-2011, 9:04 AM
So I have a 20" AR-15 that will short cycle with the large muzzle brake I have on it. However, once I take it off the gun cycles properly. Is this common? Why would this happen (what physics are involved here)? I have confirmed that this is the case by using the same ammo and removing and installing the brake several times during a shooring session.

Thanks in advance for the info.

Try lubing the buffer/buffer spring and bolt. Might work.

I'm afraid my 20" bcm upper I just bought might short stroke too.

I still haven't had the chance to shoot it. Maybe try a lighter buffer too.

FeuerFrei
02-22-2011, 9:12 AM
What kind of ammo/brake?

Sky_DiveR
02-22-2011, 9:15 AM
I've never had that experience before. Could you provide more info?

Bogart
02-22-2011, 9:33 AM
Here's a link to the Brake: http://www.midwayusa.com/viewproduct/?productnumber=637537

I don't reccomend it as it did not come with a crush washer nor does it have flats on it to tighten it down. Ruined 3 strap wrenches on this thing (has sharp edges).

I shot Silver Bear HP and some Lake City m855 though it that day, as well as the rest of my Cheap Wolf ammo (results the same across the board). I think part of the problem was that I had grease on the bolt when I should have just used some oil. So the parts could wear more easily. Using the grease I saw virtually no wear on the bolt which is unusual for a break-in.

I tried to adjust the low profile gas block several times that day. But the results were the same. (Have since put the A2 front site back on).

bohoki
02-22-2011, 12:14 PM
wow thats weird

captbilly
02-22-2011, 1:56 PM
If anything, a brake or suppressor would be likely to increase pressure and cause excessive gas system pressure/volume. Many people using sound suppressors (silencers) have serious issues with excessive gas pressure and have to make adjustments and mods to deal with it. Gas buster charging handles were partly a response to the problem of too much gas from suppressed rifles. Obviously I could be wrong (say it isn't so!) but I would guess that the short stroking is coincidental to the muzzle brake. You need to carefully look at anything else you are doing when shooting with or without the brake. You mentioned grease, were you using the grease both with and without the brake?

Nathan Krynn
02-22-2011, 2:47 PM
855 is hot so this is weird. Honestly I'd just dump the break for a much better one, you will be paying more though. I like PRI or PWS personally if not I just use the good old A2.

Bogart
02-22-2011, 2:52 PM
I've got several ideas on how to resolve the issue. Adjusting spring, buffer, gas block, etc. So I'm sure I'll get it working properly. Just wondering if it was a common issue. Sounds like it is not.

I thought I had heard sound supressors could cause cycling issues (Referencing captbilly above) but maybe that is in conjunction with sub sonic ammo.

Thanks everyone for the input.

Hump0311
02-22-2011, 3:07 PM
I see a lot more people having problems with rifles that are short stroking.

Have you performed a search on google for: "how to fix short stroke AR" ?

What length is your gas tube?

CRTguns
02-22-2011, 3:50 PM
Your gun's just embarrassed tgo be seen in public wearing that thing.

FeuerFrei
02-22-2011, 8:36 PM
A2 rifle config?
No M4ish stock setup?
When installing the brake, are you using a AR vise block and NOT just holding the upper by the ole' pinch it between the legs and twist method. The FSB can move ever so slightly to induce a gas leak thus creating a gas leak and short stroking issue.
That may explain the now it do and then it don't enigma.
Still guessing here.