I had a bit of a play with some 60gr hornady soft points in the .222 the other day
Its a factory barrel, chopped to around 20-21", 1:14 twist and "shouldn't" stabilise 60's
I had good success with 100gr in a 1:10 .243 barrelled Parker Hale which equally shouldnt have worked so nothing ventured nothing gained.
I chucked some 60gr .222 cartridges together in the lee loader and a rough scoop of around 21gr a while ago and shot a circa 3/4-1" five shot group so wanted to see what they would do if I pushed them and tried to measure charges
interestingly they group 1+" higher than faster lighter bullets
brass primers and powder as the other .222 loads I use (CCI400, norma, N133)
targets at 130yds
freezing cold day with a bit of a stiff breeze that picked up towards the end,
my wet finger wind meter measured it at 10+mph rising to maybe 15mph
started out with quite low charges as the combination of my rifle and Norma brass seems to hit max pressure well before the VV data in some loads.
the first ones didnt seal at the neck properly, soorty shoulders, could have been hard cases but suspect it was low load)
20.4gr,20.6gr, 20.8gr, 21.0gr and 21.2gr (numbered 1-5 on targets)
VV data indicates a range of roughly 2750-3000fps for these loads
The results were interesting (well to me at least!)
two shots of each the lower charges so not ideal for group indication but still shows a clear pattern
starting at just over 1" the "groups" shrank to 3/4",
next one was 7/8" but I pulled the last shot on the left a bit so am pretty confident it would be smaller if repeated,
if I only took the first two shots like the others they would be the two that are 1/2" apart,
next group opened up to 1.5"
then the next one jumped to just over 3"
all the time the rounds are getting faster (so was the bloody wind and snow!)
Al holes are perfectly round with no evidience of keyholing or tumbling, but clearly there is a sweet spot on speed but outside of this either the case doesn't obturate or the stability is very poor.
all shot off sticks while standing on one leg and using my mobile phone and chewing gum....only joking...
used the roof of the car and then discovered something had scratched the bloody paint!!
Should have stuck with the sticks!