Warning

 

Close

Confirm Action

Are you sure you wish to do this?

Confirm Cancel
BCM
User Panel

Posted: 1/15/2017 4:43:31 PM EDT
9mm 5.5" barrel, Anderson lower and sport upper Spikes 9mm buffer and carbine spring, Hann dedicated mag well. Fired as pistol a few times until my stamp came in yesterday. Seemed functionable other than a few FTF. Figured that was break in stuff. Had a stuck case. Knocked it out and loaded up 3 more on the mag. Remington 147 gr FMJ. Had form 1 7.5" b tube can mounted, which I had used during the pistol testing. Previous tests were with American 124 gr "suppressor" rounds. The one that got stuck was one of those. First 2 Remington rounds fired flawlessly. The 3rd and last one in the mag "fired" but the head separated and the bullet lodged 1/4" past the stuck case. Tried it without the can with 3 more rounds. It shot "ok", but the primer strikes look dimpled and slightly raised. And on the last case I had to pound on the charging handle to eject it.
Anyone have any ideas. I'm sure I'm missing the forest for the trees on this one.
Link Posted: 1/15/2017 6:39:48 PM EDT
[#1]
I know zip about 9mm ARs, but a couple of thoughts:

Head space issue?

Extreme over gassed condition can cause pressure issues in ARs since the bolt is unlocked and opening while pressures are still high (creating excess head space like issues.) Stuck cases, head separation seem to make this a possibility.

Did you use a head space gauge on assembly?

If not, maybe try one. If your head space is ok, look at the gas, I think.

JPK
Link Posted: 1/15/2017 6:48:04 PM EDT
[#2]
Discussion ForumsJump to Quoted PostQuote History
Quoted:
I know zip about 9mm ARs, but a couple of thoughts:

Head space issue?

Extreme over gassed condition can cause pressure issues in ARs since the bolt is unlocked and opening while pressures are still high (creating excess head space like issues.) Stuck cases, head separation seem to make this a possibility.

Did you use a head space gauge on assembly?

If not, maybe try one. If your head space is ok, look at the gas, I think.

JPK
View Quote


9mm Ar's are blowback, no gas system. May have to buy a set of 9mm go/no go gauges.
Link Posted: 1/15/2017 7:19:25 PM EDT
[#3]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


9mm Ar's are blowback, no gas system. May have to buy a set of 9mm go/no go gauges.
View Quote


Geez, even I know that at some level, can't believe I forgot.

Maybe the same issue though, if your head space is ok. Not enough spring tension or buffer weight allowing the bolt to open too early?

You can rent head space gauges. Not a lot of $'s, easy to do. Can't recall the several shops that rent them, but Google should work.

ETA: I googled; RD Reamer Rentals rents 9mm chamber gauges for $8 the set. I didn't compare pricing to other rental co's, just confirmed my recollection that renting was cheap.

JPK
Link Posted: 1/15/2017 7:39:52 PM EDT
[#4]
Discussion ForumsJump to Quoted PostQuote History
Quoted:


Geez, even I know that at some level, can't believe I forgot.

Maybe the same issue though, if your head space is ok. Not enough spring tension or buffer weight allowing the bolt to open too early?

You can rent head space gauges. Not a lot of  s, easy to do. Can't recall the several shops that rent them, but Google should work.

ETA: I googled; RD Reamer Rentals rents 9mm chamber gauges for $8 the set. I didn't compare pricing to other rental co's, just confirmed my recollection that renting was cheap.

JPK
View Quote


LOL. Talk about forgetting. I think I rented 300 BLK gauges from RD. Sheesh. Getting old.
Link Posted: 1/15/2017 8:17:36 PM EDT
[#5]
What bolt are you using?  In mine, I had to remove the extra weight from the back of the bolt when using Slash's heavy 9mm buffer and carbine spring....
Close Join Our Mail List to Stay Up To Date! Win a FREE Membership!

Sign up for the ARFCOM weekly newsletter and be entered to win a free ARFCOM membership. One new winner* is announced every week!

You will receive an email every Friday morning featuring the latest chatter from the hottest topics, breaking news surrounding legislation, as well as exclusive deals only available to ARFCOM email subscribers.


By signing up you agree to our User Agreement. *Must have a registered ARFCOM account to win.
Top Top