I assume you can manually lock the BCG back ?

And is this assm'd by you ? Or a factory setup ?... and what buffer weight and recoil spring.

Have you tried the single mag fed round trick ?  IE single mag fed round, fire, showing the BCG is going back enough to Lock the BCG back , via the bolt catch.

Ejector and spring freely working ?

Keep in mind that you have the stoner/DPMS 308 system, and the armlite system, and they are not swap-able between the platforms.

In the case of the Armlite bolt, it needs a narrow width hammer to prevent carrier wedging, while the stoner/DPMS system can use either a narrow or wider hammer.

Next is the 308 B/C stroke length to upper receiver port.  Hence you have system where the bolt will stop before the bolt face reaches the back of the ejection port, while there is a what is  called a long action on a short ejection port upper where the bolt will retract past the back of port to get back past the bolt catch, and on this type of action, the special bolt is needed to make sure that the ejection of the spent case is correct.  Also, 223 and 308 receiver extension parts are not interchangeable in regards to carbine system.

To sum it up, need a complete break down of the specific parts in play, and if they are system compatible for the 308 system being run.