I have finally gotten loads that I like developed for both my 223 Ultralight and 357 Maxi barrels.
The 223 gives me an honest 3024 fps out of the 20" Ultralight barrel with the 55 gr Hornady SP and H4895, and shot a pretty good group: not tiny, but no Handi Syndrome fliers. This was better than the same powder charge and Nosler Ballistic tips, quite a surprise.
The 357 Maxi gave me 1856 fps with the 180 gr SSP and H110, and put 4 shots in 15/16". There was still sort of a flier, but with a 1 inch group, who cares ?
I also tried 2400 with the SSP, but it shot a 4" vertical group, and the action popped open on the last round I fired. Never had that happen before.