I am experiencing some issues with weak extraction shooting Prvi M193 in a Stag Arms model 2 barrel. I have the following information to help troubleshoot.
Any ideas?
Sounds like week ammo or your gas key is loose. Check your gas key and try some other ammo.
It’s possible the ammo is weak but it is Prvi M193 so it should be of good quality. I tried another BCG and it has the same problem. The gas keys are staked properly.
Try the ammo in another gun?
Have you tried any ammo other than the prvi? I know it’s good stuff and a little pricey (for my cheap ass), but it does happen.
Are you using a standard carbine buffer spring? Or are you running one of the extra strength ones that are a little longer to reduce muzzle flip and felt recoil?
It’s not a rifle length spring is it? I know that sounds stupid, but it’s happened.
That’s really all I got for you, man. Me no armorer… me just shoot paper bad guys in face a lot:p
Semper Fi,
-Paul
Is it a new rifle?
If not, did it once work and now it doesn’t work?
Does it lock back when cycling manually?
Sounds like you’re undergassed, probably due to improper gas block installation. Who installed the gas block, Stag or you?
Stag AR’s are generally over gassed. PRVI ammo is usually pretty good.
Has the Stag ever ran correctly? The gas block could be off or the mags you are using are bad (weak springs).
C4
Weak extraction? It is extracting and ejecting but you feel it is not forceful enough? Why, because the bolt will not lock open after the last round? If that is the only indicator Grant may be correct regarding the magazines. Also it could be a broken or sticky “bolt release.”
If you have symptoms other than the bolt not locking open, in addition to the other suggestions, you may also want to:
Check your chamber
Check for signs of gas leaking between the carrier and key (you will normally see it in the front right corner of the key, as you are looking from the back of the carrier)
Check for signs of gas leaking around the gas block
Check your rings
Is your rifle clean?
Here is some additional information.
-I have used this ammo fine in another rifle.
-I tried 2 bolt carrier groups that are new. Both have same issues.
-Manually locking the bcg back works.
-Rifle is clean and lubed (running it wet).
-Using a standard carbine spring.
-Magazines are tested and working properly in other rifles.
-Rifle has less than 100 rounds through it. No FTE’s or FTF’s.
Is it possible the chamber is too tight and slowing down the BCG? This is my first time firing Prvi M193 5.56 from this particular barrel. I am going to go to the range on Monday to try out different ammo to see if its ammo related.
Sounds undergassed.
My guess would be the front sight block is not aligned with the hole in the barrel. Or there is a pretty significant gas leak. Less likely would be too strong of a buffer spring.
I too think you likely have a lose carrier key. Stag does a poor job of carrier key staking and IMHO they don’t torque the screws high enough.
Sounds like your extraction is good but ejection is weak. As long as the cases are making it our of the rifle I would worry about it much. Just be sure the ejector is lubed well.
What mags were you using?
yea leaning towards gas system problem now.
My BCM middy with H buffer and BCM BCG shoots underpowered wolf all day long with no problems. I doubt it is ammo related, I never had a problem in any of my guns with Prvi M193. If my guns can eat wolf it can definately eat real stuff
I switched out the carrier group with a BCM carrier group and experienced the same issue. The extraction is fine but the ejection is very weak. It kind of plops out of the rifle rather than being thrown out. I am using 20 round Pmags that work fine in other rifles.
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I would check the chamber its possible it needs to reamed to a 5.56 chamber.
Early Magpul 20 round PMAGs have trouble locking bolts to the rear when the rifle runs empty.
Does it lock to the rear with a 30 round PMAG?
It could just be the mags. If you have a 0-ring on your extractor remove it and the ejection force should throw the empties further. You only need the 0-ring on CAR length gas guns.
I have not tried with a 30 round pmag. I will test that on Monday along with different ammo.
I do not have the O-ring installed. I am using only the black insert with spring kit that BCM offers.
I am suspicious about this being the issue as well.
That extraction setup is just fine.
C4