Muzzle Break causing feeing issues? Update

[rockchalk06]

***Update***

I'm calling the issue fixed. Only variable I changed was loaded the ammo a tad warmer. Thanks to all that helped.

I swear I am loosing my mind here.

First 4-5 ranges trips with my Aero SPR, no issues at all. Running standard A2 flash hider. Last two trips, other than the optic, only thing I changed was the A2 to the VG6 break. Last Saturday, I had numerous what I think is short stroking where the round is below the bolt. Bolt dug into the round.

First thought was mags. I was using 1 Lancer FDE 20 round mag. Changed to a different mag, same issue. Went home, cleaned and lubed everything well.

I ordered 7 Magpul 20's, numbered them and of the 3 I brought today, same issue. It's sporadic too. Never the same round number etc. Always the same type of feeding issue. Bolt has dug into the round, on top of it with the round pointing high in the chamber.

Ammo the either life of the rifle has been the same. Berger 77 grain OTM loaded to mag length. Same charge the entire time. I'm on the low side at 19.5 grains, but pushing about 2350 FPS.
Same range set up. Bipod and rear sandbag off bench.
Rifle and Lancer mag ran like a champ until the change from an A2 to the VG6. Note here, recoil is significantly reduced here too.

I checked the gas block, screws are torqued at 30" pounds
Rifle length buffer with spring are correct, clean and free of any debris

It feels undergassed to me after the break install. I would have argued with someone 20 minutes ago if they told me installing a break would cause this, but I read this thread and now I'm not sure of anything now

https://www.ar15.com/forums/AR-15/Short-stroking-caused-by-muzzle-brake/121-753471/
Obviously the next step is to remove the break and reinstall the A2 to see if this fixes my issue. Anyone had a similar issue and fix?

Thanks in advance OSA

 

[red442joe]

I am currently working on an AR pistol that supposedly has erratic "jamming issues.
Other than a bunch of little problems that may contribute....the gas adjust screw is gone!
Nobody said it is NOT running......
Due for it's range trip.
Try yer old brake, I guess the problem could be there. Good luck.

Joe

 

[HiredHand]

Did you try loading one round in the magazine and seeing if the bolt locks back after the round is fired?

 

[rockchalk06]

Did you try loading one round in the magazine and seeing if the bolt locks back after the round is fired?

It does "sometimes". Drives me nuts too.

Edited to add, it would lock back everytime prior to the VG6.

 

[conditionzero]

I know SPR are usually running an 18" barrel, are you? I know that brake is tuned for 18 but not over. That said, no more or less gas should be getting past your gas block all things considered. That break should only be directing the existing gasses.

I know you know that, and that is why this is so puzzling. What I would do is swap back the A2 and see if the issue goes away. If it does you know it is the device, if it doesn't something else is up.

 

[JEVapa]

Last Saturday, I had numerous what I think is short stroking where the round is below the bolt. Bolt dug into the round.

From what you are saying, it sounds like the BCG is overriding the cartridges in the mag. Like what @HiredHand said, if it's locking to the rear on the last round, then you can be overgassed.
If it locks back occasionally on last round, then it's something different...undergassed or H buffer.
If it's having any FTE issues, then it's probably undergassed or too heavy buffer, etc. If it's ejecting no problem, I'd say it still may be over gassed. Basically it's going too fast to strip a round from the mag unles you know for sure that it's shortstroking - see the single round bolt lock eval above. I'd get 20 mags with one round each, and shoot them and see how many times it locks to the rear.

I've never heard of a muzzle device impacting a rifle so as to make it malfunction outside of an improper installation or improper shooting fundamentals - limp-wristing with an effective MD can possibly shortstroke.

 

[rockchalk06]

I know SPR are usually running an 18" barrel, are you? I know that brake is tuned for 18 but not over. That said, no more or less gas should be getting past your gas block all things considered. That break should only be directing the existing gasses.

I know you know that, and that is why this is so puzzling. What I would do is swap back the A2 and see if the issue goes away. If it does you know it is the device, if it doesn't something else is up.

Yes sir. 18" with rifle length gas tube.

You are correct, my brain is telling me no more or less gas is being directed into the port than it was prior. The break would essentially cut down on inertia, but this is a gas gun and that makes my brain hurt more.

The only other issue I can think of would be something in the gas system has gone bad, broke or something.

 

[Gunbuffer]

Ambient temperature

 

[rockchalk06]

Couple of other things I've looked at

Gas Key is tight. It was staked by Aero.
No abnormal wear around the gas tube or where it meets the key.
Bolt (when extended) holds the weight of the carrier group
No signs of gas leakage around the gas block either

 

[HiredHand]

Ambient temperature

Thinking the low charge weight and temperature sensitivity might be causing an issue? Testing with a factory load or bumping up the charge weight would be a good check.