Okay, after calibrating scale to 400 grain test weights. I re-weighed the original 2, and 3 others.
400.6 400.7 400.7 401.3 403.1
FWIW Gentlemen, from an accuracy/hunting standpoint, i was able to fire a 5 shot 10 inch group at 1100 yards with my 50-90 Sharps rifle with Hoke tang sight and Distant Thunder front sight, those 720 grain paper patch bullets from that casting session ran the needle on my RCBS 10-10 scale to + or - 1 grain, so two grains max difference total bullet weight still allowed me to easily hit the vitals on a bull elk, moose or buffalo at that extended range, i shot prone with bag under barrel and rifle against shoulder, perfect conditions, no wind and overcast skies.
Guys like Ranch13, Kurt71, Kenny Wasserburger and maybe even Saint Bagwell match shooting may not allow +/- 1 grain bullet weights to pass a casting session inspection, particularity in the 500/560gr weight class of bullets i wont allow it in 40 and 45 cal bullets, but plenty good enough in the Big 50 banging around on farm steel, i haven't and wont weigh the 450gr TSX's Sir Ron gave me, for 300 yard max hunting range it simply wont matter.
