.308 Build/Fitment/Firing Issue

[daveblack]

First post here. Hope the knowledgeable members can help me with my build. This is my second build, but I am not 100% sure what is going wrong.

Built a .308 with these parts:
-Aero upper
-DPMS Gen 1 lower (non-Aero)
-Faxon Firearms Low-Profile Gas block (fixed)
-Heavy Rifle Buffer (9oz)
-Armalite Buffer Spring
-Fixed rifle stock
-Luth-AR 308 Bolt Catch

There is a gap when I connect the upper and lower. You can see where the Aero upper hole does not align with the rear takedown slot. I can get the rear takedown pin only by hammering it in. Picture is with the front takedown pin only.


I have tried a different upper and I have the same fitment issue.

When I fire it, the round ejects, but the bolt only goes back halfway and the next round doesn't feed right. Can pull bolt all the way back with the charging handle to reload manually.


Any ideas?