[thesurvivalshop]

I believe most of the Receiver face imperfections are from finish applied to the Receiver , some manufacturers may be more than that , but it seems to me to not take a lot of work to have a flush fitment with the Barrels Extensions Flange . Always give that Flange a look over also , just because .

 

[bfoosh006]

I have PTG , Brownells and a Wheeler..... they each fit slightly different upper "types".

YMMV,

The PTG ( Pacific Tool and Gauge ) fits most all AR15 uppers great and is my goto lapping tool. ..but, that is provided the upper isn't a thermal fit upper.

The Brownells fits "thermal fit" ( Like a BCM / SOLGW ) uppers perfectly .... The PTG won't even fit into a BCM thermal fit upper, the Brownells does.

The Wheeler one I tried, was such a poor fit on any of my upper brands... it now serves a internal buffer tube polisher.

FWIW... I don't put the upper into a vise, Imho, it is to easy to induce a slight off center pressure when it is in a vice. ( Well, it is for my typical "Bigger Hammer" mentality )

I prefer to lap the upper vertically and while everything is hand held. Oil the shank adequately and don't lap at the highest speed, let the drill do the work... don't force the upper onto the tools face to speed up the lapping.
Hand holding the upper to the lapping tool, for me, makes it easier to feel what is going on.

If you are lapping the receiver face.. consider shimming or Loctiting the barrels RE in place.

 

[MuppetMeat4Me]

FWIW, Wheeler finally got back to me and said, "China."

I went Brownell's based only on that. We shall see what fun awaits!

 

[IALoad]

I have the Bart tool made by xcaliber barrels. I’ve gotten along pretty good with it the last couple years. Part of the reason I bought it was it doubles as an action ride for assembling the upper receiver.