Precision Firearms upper to tight to fit lower RR lower AR15

[Sticks]

I am no fan of PF, however... their upper I have fit on 3 different lowers. Two PSA lowers, 3 years apart circa, and one Noreen Billet.

Could be that there is a slight tolerance stacking going on with your PF upper against your RRA lower. Don't know, and since it has been tweaked to fit, it is no longer a matter of concern.

[LRRPF52]

I would have sent the PF back to PF and tell them to make it to industry specifications! Don't sound "precision" to me! If they only make their uppers to fit their lowers then so be it but they need to specify that! I have built a lot of uppers and those that went on RRA lowers did so without any problems! Of course I am just a "common man"

OJD

I've seen PF billet receivers that fit so tightly together, you almost didn't need pins.

Billet receivers made for that level of precision fit are a bad match to mount onto forged lowers from the bargain tier.

Rock River machines their takedown lug recess mate-up differently so that their receivers will initially feel really tight.

They will often wear out their fit if you apply dynamic tension when shooting a lot, and get sloppy.

I should have caught that earlier about this not fitting on an RRA lower.