Not quite mil spec - ZEV Technologies AR15 Forged Upper Receivers

I bought this a little bit ago because ZEV parts have always been great for my glock, and they look good, and this upper was only $120ish even tho it is stripped.
but then I looked at matching handguards and they are $250-300!
I start putting it together and the barrel (Ballistic Advantage PREMIUM series) wouldnt fit, I had to lube it up and pound it down with a nylon hammer. then the back take down pin was way off, from my lower. so i had to file it down. I know usually not everything fits perfect but this was the worst one.

then the handguard putting that on is a chore, you have a TINY pin you put above the gas tube to make sure the guard and upper dont twist. then the wedge lock takes forever to tighten down and its at the worst angle. then you have these other two TINY screws you put in. and it has a special tool to tighten the barrel nut