[ARCHIVED THREAD] - QC10 AR45 Feed Problem

Posted: 1/27/2017 8:18:55 PM EDT

I've built a Q10 GLF 45AR and it feeds intermittently - some rounds appear to get caught-up on the top of the chamber as they are going into the breech. The bolt doesn't completely close.
See images below.

When the rounds are extracted they have an indentation from the top of the chamber on them.

The issue seems to be worse when running unsuppressed without the can so I'm thinking the cyclic rate is too high because of the buffer being light.
I'm using both OEM glock 21 (13rd) mags and also some aftermarket 26rd ones which I suspect are the Korean made ones.

My theory is that the rifle is cycling too fast as I'm using a 9mm buffer (waiting for my slash buffer to arrive from the US to NZ

)
Its possible the bolt is moving the rounds off the mag-stack too fast and they are getting caught because as one round comes off the mag another pops up - pushing the one going into the chamber up at the rear of the case causing it to snag on the top of the chamber.
I did polish the chamber-top heavily to reduce this issue, which seems to have helpt as when I initially built the rifle virtually none of the rounds were chambering at all - even just loading the first round would not chamber properly.

So my thoughts are - 1) - get the right buffer, and failing that working 2) polish the chamber more to aid feeding.

Appreciate any advice you guys have with 45AR feed issues - related to glock mags and the QC10 45AR builds anyway.

Posted: 1/28/2017 12:39:04 AM EDT

[#1]

You need to get the buffer weight up around 10 ounces for a blowback 45.
actually raising the mag height a little may help as well.......see if you can super glue a .020 shim on the top of the catch and see what happens.....
Shoot me an email and send me some pics of the breech/chamber mouth of the barrel.

Posted: 1/28/2017 2:16:57 AM EDT

[#2]

Quote History

Quoted:
You need to get the buffer weight up around 10 ounces for a blowback 45.
actually raising the mag height a little may help as well.......see if you can super glue a .020 shim on the top of the catch and see what happens.....
Shoot me an email and send me some pics of the breech/chamber mouth of the barrel.

View Quote

Will do cheers. What catch are you referring to? The mag catch?

Posted: 1/28/2017 8:57:34 PM EDT

[#3]

Yes...the mag catch....
Possibly correct with a slight feed cone modification......what length barrel?

[ARCHIVED THREAD] - QC10 AR45 Feed Problem

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[ARCHIVED THREAD] - QC10 AR45 Feed Problem

[ARCHIVED THREAD] - QC10 AR45 Feed Problem