I posted this in the AR Discussion forum and only got one reply, so I figured I'd see what response I get in the Builders' forum.



I built my AR with a J&T 16" A2 kit on a DPMS lower. After accessorizing a bit I want to take it to another level. I want to replace my upper with a flat top.

My upper was full assembled and headspaced when I received it, so I don't have experience in assembly of the top end.

Any advice on getting a stripped upper and transferring the components from my old receiver?

I figure transferring the barrel to the new receiver is most likely going to be the most critical step.  Any tips?

Any pitfalls to be aware of where I could royally screw things up?

Anything that should be done by a bona fide gunsmith?

Any tips on rear sights? I've seen uppers with rails at various heights.

My plan is to also install a piston kit, now that they have hit the market.

Any advice is appreciated.

OK, I violated a fundamental rule here.  I posted my questions, then started looking for the answers myself.  Got it backwards.

The tacked assembly thread is great.

Of course, any advice is still appreciated when I'm going into new territory.

yea, advice is only part that is of significance is removing/installing barrel which you've found