Okay I figured you guys could clear this up… is the area where shells are striking normal or does it indicate an over gassed upper.
Mid-length with H buffer, ST-T2
As far as I have seen that is completely normal, any AR I’ve seen with more than a few rounds through it has roughly the same mark there.
This subject has been touched upon numerous times in recent months.
The orange search button at the upper right hand portion of your screen works well.
Please use it.
To answer your question, it is 100% normal.
Normal, quit being anal. Go shoot.