Thanks, Daryl; for posting those photo's for me.
The Group is thirty shots total, three fliers, so 27 shots in the .504 group. The catridge is a
20 Vartarg, based on a .221 Fireball necked to 20 cal. with a sharper shoulder, the case in the photo has not been fire formed. Fireball cases are very hard to come by, but can be made from .223 Rem./5.56 nato. Using 18-19 grains of several different powders a 32 grain bullet will be between 3800-3900fps 10 feet from the muzzle. I've handloaded 50+ years and can say this is one of the most accurate and easiest cartridge I've ever worked with.
Bob