When I had my SS .223, my load was:
27.3 gr. Varget
50 gr. V-max
CCI BR-4 primers
LC brass (mixed years)
COAL was 2.3" long
Trimmed to length with LEE case trimmers and loaded on a LEE loader,
they consistantly stayed under 3/4" for 5 shots, and under 1/2" for 5 was
possible if I cut back on the caffeine. That was with a 1/12" twist barrel.
I don't know the speed since I don't have a chronograph, but all I know
is.....the groundhogs aren't talking.
~Amos