Freq Hate to ruin your understanding of what a quality ar308 or ar15 for that matter should look like.... you said.."If it were fitted perfectly, you would get a mechanical lock and wouldn't be able to pivot the upper off the lower" bullcrap on that statement ... Ive got many ar308's and they are so tight you can hardly see the line separating the upper and lower... and they pivot fine....i wouldnt own a piece that looks like yours...but thats just me Wash