lol, yeah....not concerned with my arsenal ak, it's the ar type rifles. i have in my mind tolerances would be tighter on the american manufactured product. maybe not, might be "ak sloppy."
First off, I don't have an AR in x39mm and I no longer have an SKS, so I can't chamber check anything anymore.
In the past, my F-L resized cases would often not fully enter the L.E. Wilson head space case gauge. This wasn't due to improper shoulder dimensions, but rather due to too large of a diameter at the base and rim of the case; in the area where the die doesn't make contact. Insert the base of the case first and you'll see it bind.
I suspect they would chamber okay in an SKS; don't know about an AR. It's not uncommon to have a burr on the rim that can cause the misfit, but that wasn't the case in this instance. Simply used a little touch of a file or other medium to bring down the diameter slightly to enter the gauge fully. Again, this may not really be necessary, but I did it on many over-sized cases. A small base die would not contact this area of the brass either.
Remember, the Wilson HS Case Gauge is not designed to measure case diameters, but rather shoulder placement.
As mentioned, run a few through your press and chamber check the sized cases. If they fully chamber, you are sizing adequately already.
Cheers.
BTW, that company named after the great WWll naval battle has the Inceptor Sport Utility Bullets 7.62x39mm (311 Diameter) 90 Grain SRR Spire Point Frangible Lead-Free Box of 250 for around 10 cents a pop; on back order, of course.