Those holes look mighty concentric to me - but I guess just a small amount of yaw would be pretty hard to see on paper.
It's funny, I just measured some of these boolits that I'd run through a Lyman 45 lubrisizer with a .311 die back in December 1970 - they measure in right at .309". Do you suppose these boolits shrank .002" in 39 years?
TexRed told me about Wilk gas checks last night in chat. Very interesting! I added a link to an article over in the 311413 thread about that. A fellow by the name of Ed Wilk came up with the idea of punching a hole in the bottom of a GC so that you could add GC's to cast boolits that the mold wasn't designed to incorporate. You just pour alloy right through the hole in the GC.
But then the idea was taken further; use another holed GC further forward in the boolit mold, say on the 1st drive band. This gives you a pair of brass or copper reinforcing points on the boolit, which helps a great deal to prevent the boolit from getting cocked sideways. In the article, they were using the Wilk GC method for 7mm, and getting very small groups at 2,800 fps! Won't be able to push these boolits that fast, but 2,300-2,400 using slow powders should be quite do-able.
One thing they don't mention in the article is adhesion of the alloy to the GC's. If you've handled the GC's at all, you'll get finger oils on them, and the alloy won't flow on the GC (think soldering) so it would actually weaken the boolit when used on a drive band. However, I will clean my GC's before hand with isopropyl alcohol, etch them for 30 seconds using a muriatic acid bath (available at pool supply stores; don't breathe this stuff) and tin them using a Sn63/Pb37 solder pot I have. Might be a bit tedious, but it's just a test. If it works really well, I'll figure out a faster process later.
If I can find my danged boxes of .30 cal GC's I'm going to give it a whirl, and try them in .30-06 with 39-42gr of Varget and 45-48gr IMR 4350, which are the slowest powders I have on hand right now. That should get them going around 2300-2500fps