AR 15 failures to feed/lock open

[Hawk]

I just purchased a White Oak 20" match upper with a Wylde chamber and I'm experiencing many failures to feed and failures to lock open after the last round. The lower I'm using (MEGA Gator) is borrowed from my m4gery which has never had an issue when mated to my 16" upper.

Additional Info:
-Wolf ammo 55 gn fmj & hp (haven't tried the Wolf 62 gn) would it matter?
-New upper only has 150 rounds thru it so far -break period in?
-I've clean it twice and shoot it wet.
-Checked gas key and it's tight and double staked
-Verified the gas rings are not aligned
-Tried 4 different mags that worked in the lower when it was on the m4gery

Any other suggestions?

Hawk,

[TonyF]

Classic short stroking so you may still have a gas leak. Does it have an aftermarket gas block? One way to check is to shoot it at dusk and have someone watch to see if they see flash at the gas block.

[JayBell]

more possible on this, its the ammo.

my latest build was a 20" colt barrel target gun...the gun definitely has no gas leaks and is properly assembled.

the new wolf 55 and 62 gr ammo I have will not cycle it properly unless I have my suppressor on it....meaning its weak low pressure ammo, as the suppressor is providing more gas pressure to cycle.

this further tells me its weak ammo, as standard milspec like Lake City, Black Hills and the Igman stuff i just bought cycle it fine.

Commercial softnose hunting ammo by Winchester also ran perfect.

Latest wolf i have wont cycle my FS2000 and barely works in my 223 AK, and gives a weak report and barely cycles in my 11.5" SBR so for me, its the ammo for sure.

try a standard brass cased loading if you have any, try one shot in the mag and see if it locks open/cycles, before loading more.

[Hawk]

Originally Posted by TonyF

Classic short stroking so you may still have a gas leak. Does it have an aftermarket gas block? One way to check is to shoot it at dusk and have someone watch to see if they see flash at the gas block.

That was my first thought too. But, it's not on every round (1 or 2 out of ten) John at White Oak said he tested it before shipping and it functioned flawlessly, he said to ship it back and he would check it out and make it right, but before shipping it he recommended running some other ammo (besides Wolf) through it to see if it is the ammo. BTW, it extracts and ejects normally.

Would shooting 62 gn Wolf throught it instead of 55 gn Wolf make any difference?

Hawk,

[markheck1]

Wow! you guys are always so quick and informative with this AR stuff

Can't wait to get one!

[Hawk]

Originally Posted by JayBell

more possible on this, its the ammo.


the new wolf 55 and 62 gr ammo I have will not cycle it properly unless I have my suppressor on it....meaning its weak low pressure ammo, as the suppressor is providing more gas pressure to cycle.

this further tells me its weak ammo, as standard milspec like Lake City, Black Hills and the Igman stuff i just bought cycle it fine.


try a standard brass cased loading if you have any, try one shot in the mag and see if it locks open/cycles, before loading more.

Thanks JayBell,

I too believe it's the Wolf ammo. I was thinking about getting some Igman at ammoman, but I need to confirm it's the ammo first before I buy a 1000 rounds.

Hawk,

[TonyF]

Originally Posted by Hawk

That was my first thought too. But, it's not on every round (1 or 2 out of ten) John at White Oak said he tested it before shipping and it functioned flawlessly, he said to ship it back and he would check it out and make it right, but before shipping it he recommended running some other ammo (besides Wolf) through it to see if it is the ammo. BTW, it extracts and ejects normally.

Would shooting 62 gn Wolf throught it instead of 55 gn Wolf make any difference?

Hawk,

It could well be the ammo but I don't think the marginal increase in recoil impulse of the slightly heavier 62 grain will make much difference.

Dick's seems to have a good supply of Remington UMC 55 gr FMJ. Pick up a box and run a couple of mags through it.

FWIW, Federal's american eagle brand of 55 gr FMJ is notoriously under-powered and I've never had an issue with it cycling my 20 inch uppers.

[Hawk]

Originally Posted by TonyF

It could well be the ammo but I don't think the marginal increase in recoil impulse of the slightly heavier 62 grain will make much difference.

Dick's seems to have a good supply of Remington UMC 55 gr FMJ. Pick up a box and run a couple of mags through it.

FWIW, Federal's american eagle brand of 55 gr FMJ is notoriously under-powered and I've never had an issue with it cycling my 20 inch uppers.

I'll give that a try and let you know the results next week.

Thanks,
Hawk

[Lambo]

Did you try various Mag Manufacture? Alot of After Market is Junk!

[Mity2]

I'm thinking short stroking. If bolts aren't locking open, its got to be short stroking. I've personally never had any issue with Wolf ammo. Have you try other bland of ammo to see if thats the case?