AR upper assembly question

[Bat Rastard]

I started disassembly. Examining the mating surface of the handguard I found no evidence of it making contact with the receiver. There will be no grinding at my house.

I am indeed using a bag rider.
Thanks again !

 

[Fast14riot]

Barrel, bolt, trigger. These are the 3 biggest factors in AR precision. Everything else just supports those.

Start at the beginning, load, sights, position and follow through. Scope parallax, tracking, mounts.

 

[6Creed73]

I've built dozens of ARs from stripped recievers over the years, mostly because it's fun to build them, and because I just like the platform. Aside from my main 2-gun rifles, the other 6 or so are just range toys that I try to squeeze as much accuracy as I can out of. When it comes to accuracy, the main thing I've learned is never skimp on the barrel. I've used many barrel brands and by far my favorite it Criterion. I like the Wilson Combat match barrels too. next is BCG, then trigger.

Everything else is diminishing returns as long as everything is in spec. This is of course assuming your scope is mounted well and is holding zero. Your handguard is free float, so I can confidently say this has little to nothing to do with your accuracy.

I'd break the upper down completely and then check the fitment and re-torque everything. When you torque the barrel nut down, you'll want to torque it, loosen it, torque it, loosen it, then torque it again to stretch the threads. This will ensure your barrel will stay nice and tight. Happy shooting!

 

[akajun]

Couple things
Yes the hand guard should not be touching the upper behind the tenon. So relieve it .030 clearance. Two make sure the gas tube is not touching anything , hand guard, weights, etc. make sure it’s centered in the upper and the key can move smoothly onto it without binding .
Lapping may help but I find that barrel extension fit to the upper is more important . I’ve shimmed them but some people are using bearing retainer too