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Suppressed XCR-L not cycling with subsonic ammo

2K views 4 replies 4 participants last post by  navalbeaver 
#1 ·
Suppressed XCR-L not cycling with subsonic ammo

Anybody have an idea on why my suppressed XCR is not cycling subsonic 300 blackout ammo? It functions fine with supersonic ammo both suppressed and unsuppressed. However, no matter what subsonic factory load I use, it will not cycle. I have tried all the piston settings.

My XCR-L is one year old. It came from the factory in 300 blackout. It is equipped with an OSS Elite suppressor. The barrel is approximately 12 inches with a buried gas block.

It has less than 100 rounds through the gun. Could that be the problem? I seem to remember reading about a problem with the manufactured piston, but I can’t seem to find anything now. Any ideas?
 
#2 ·
The OSS have very little to no back pressure, most 300blk subs are slightly underpowered to avoid overgassing ARs which are usually overgassed, so between not getting the extra oomph that most suppressors provide from back pressure and low powered ammo... voilla you have a straight pull bolt action!!!!!

what ammo are you using? They are not created equal.
 
#3 ·
I was wondering about that myself... The OSS designed for little to no blowback in the face... that might change the whole dynamic. The subs I have used are Remington 220 grain and Hornady 208 grain amax. Would breaking in the rifle with a couple hundred rounds of supersonic help?
 
#4 ·
RA recommends 200 rounds of "hot" ammo (not subsonic) through the gun to "break it in". Personally....I've never seen that method actually work. The gun either works or it doesn't the first time you use it, IME....and running additional ammo through it has never cleared up a problem XCR of mine (I have like 6).

It could be as abran said....your can's flow through system may not create enough back pressure to run, but that's just a guess. If it won't run on several different subs of .300BLK....then a call to RA is in order.

You may also want to check your gas dial and gas block/bbl port sizes to make sure they are the correct ones for the .300 BLK. There have been instances of the wrong dial being shipped with the gun (my .308 12" -M was shipped with a 5.56 dial by mistake).
 
#5 ·
+1 with what Sean said.

I've generally findf the XCR to be over gassed. I'm pretty confident I could get mine to run with subs without a can but each rifle/round has its own intricacies. I've also seen some variance in gas port/block/dial sizes as well and have done that are more restrictive than others
 
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