Okay, so I had some time this evening to go up to my shop and measure a few things. I took the heaviest case I have come across and the lightest case, and took a H20 capacity measurement from both of them as well as measured the neck wall thickness in 3 locations on both cases and the I.D. of the case mouths in two locations offset by about 90*.
M118 2022 brass
Case H20 Capacity between the two, 53.9gr and 53.6gr
I.D. averaged at .302"
These measurements were from sized brass.
0.005" tight on the I.D. does seem a bit tight... I did order some Imperial dry lube... which I ASSUME is graphite. Just like I ASSUME the Hornady one shot is just graphite in an alcohol solution or something to spray the cases with? Also got a Hornady seating die in the mail to see if it's stem will fit better in general. If not then I'll modify the old die's stem as discussed above with JBWeld... I assume oil on the bullet would work as a release agent once the epoxy starts to set a little?