New AR 15 build questions

[Islas82]

Hey guys so about a month ago I decided to put my first AR together and for the most part am pretty happy with it. Only issue I have now is that I think the buffer (Armspec SRS 3.8oz) might be too heavy so bolt is not locking on the last round but gun is cycling fine with the 3 different types of ammo I have ran thru it. Just got back from the range and noticed something strange and was wondering if I could pick y’alls brains. Picked up my brass to inspect and I notice a dent on all of them (see pictures) any idea what could be causing this or if I should even worry about it? I shot .223 norma 77s and frontier 68s today the dents are only on the frontier casings, norma brass looks fine.

shooting a 18” aero precision .223 wylde barrel with a rifle length gas system.

thanks

 

[smokin.338]

Your rifle is overgassed hence why it won't lock back... and it's flinging the cases into the deflector.
Cheap band-aid = H2 w/ carbine spring (may have to step to a 308 spring)
The right way = Adjustable gas block

 

[RyanScott]

Jesus, how do you cut a port big enough to overgassed that combination?

 

[Islas82]

Your rifle is overgassed hence why it won't lock back... and it's flinging the cases into the deflector.
Cheap band-aid = H2 w/ carbine spring (may have to step to a 308 spring)
The right way = Adjustable gas block

Have an adjustable gas block on it already, I will play with it next range session.

 

[Islas82]

Jesus, how do you cut a port big enough to overgassed that combination?

I know man, I thought that with a rifle length and a H buffer I wouldn’t have any gas issues.