Facing the Aero Upper

[bamashooter]

Reporting back. Function has been perfect with the Aero Precision rifle build. I've not chronographed any loads, but my old standard 55 gr. Sierra with 26.5 grs. of Winchester 748 produced .650 inch 5 shot groups at 100 yards. The 65 gr. Sierra and Speer 62 gr. both show good promise. Varget and 748 have produced the best groups. I wanted Tac to work, but so far no glory. The Hornady 75s are not working for this rifle. Next will be some 77 gr. class bullets.

Just curious, has this gun been assigned to a specific task?

[JStor]

Not really. I guess I was just going to see if a build could shoot any better than a Colt HBar Elite. The first 100 rounds shows that it will. My range is limited to 300 yards, but if I fix up portable targets I can move beyond my boundaries.

[Cold/Bore]

Yes, it is possible to lap the receiver face of the Aero M4E1 receiver. This company makes the appropriate lapping tool: https://www.x-caliber.net/bart-20?fb...SF0tnTOey3B0eg

There was another company (g and g rifle works) that also made a similar tool, but their website is no longer available so I have no idea if they are still in production.

[rpoL98]

I did an Aero M5E1 ("308" large frame upper) using the afore-mentioned X-caliber tool. The tool worked like it's supposed to. I know it's not exactly what you asked, being the large-frame AR instead of the M4E1, sorry. Figured it's kinda close.

[hopegunworks]

I'm really late to this game, but, I check it on each and every upper. NO I don't use the Drill Powered tool. I built a tool years ago that is a fixture with .0001" TRO. I place the Upper on this jig, insert it in a 4 Jaw Chuck adjust of .0001 TRO at an indexing area just beyond the Barrel Stop Ring Mating Surface. Once "zeroed" i can now check Concentricity and Perpendicularity of the Receiver Flange to the Long Axis. Here's the important part, first I measure. To quote an old James Gang Tune "Garden Gate" - "The captain’s in the chartroom Navigating on a star, Can’t know where we’re going 'Cause he don’t know where we are" I also check the CL of the rail for Parallel to the Long Axis of the Receiver (both axis). It's surprising the number of Uppers that are off in this dimension. I guess the concept here is "they got windage and elevation adjustment". But, on a Billet????
As to the original question I have found big $$$ Billet uppers off of perpendicularity by .003". I have also found $39 Mil-Spec perfect.
Light weight 20221129_080358.jpg