Bolt won't stay open after mag empty

[3delta]

After firing the last round in a mag the bolt won't stay open. After removing the mag and manually attempting to lock the bolt back the bolt slides over the latch. The latch is free and not binding and appears to be operating fully. With the mag inserted I can pull the bolt to the rear and the Magpul magazine will then hold the bolt back. The rifle is a DPMS complete upper and was assembled at the factory. The lower is an 80% lower and the lower parts kit is DPMS. The pin to hold the bolt catch is threaded and as stated appears to be fully functional.

Any suggestions will be appreciated.

[98Z5V]

The lower is an 80% lower and the lower parts kit is DPMS.

 

DPMS 308 lower parts kit?  Or, DPMS AR-15 lower parts kit?

 

The bolt catch really makes a difference.  And, the DPMS 308 bolt catch ain't the greatest.  The AR15 one will commonly leave you in the situation you're in now, though.  Don't work so well in a 308 AR.

[Dane Armory]

9 out of 10 times the bolt catch is too low in height .

Armalite AR10 bolt catch should solve this issue !

[3delta]

The lower parts kit is for a 308. I ordered another bolt catch.

Thanks for your help.

[mineralman55]

How many rounds through it? I needed ~120 before the bolt would lock back. Break in is important.

[3delta]

About 25. I was breaking in the barrel per DPMS instructions.

I found the problem. I ordered a magpul prs stock for a 308. It came with two buffers. Both the same. Well as it turned out both were to long. The rifle functioned well except for the lovking back problem. After further inspection I found that both bufferes supplied were to long so I ordered the right one.

[392heminut]

That would do it! <thumbsup>

[3delta]

Got the correct buffer today and all is well. She's a winner. Now to get her properly broke in and work up some loads.