Here's another anecdotical cpmparison, not with H-4350, but rather H-4831.
Via a PacNor, 1:10" twist, 23" long, #3 contour barrel, chambered for the .257 Ackley Imp., my 'old' pet load, using H-4831, and 110 GR. bullets, shot over an Oehler chronograph, cenetred 15' from the muzzle, depending upon the day, produced average of 3070 -3080 FPS. The load consisted of a nicely compressed charge, but as measured by bolt-lift and case-life, was a mild load, which produced sub 0.5" 5-shot 100 Yd. groups. A pretty decent hunting load.
I was very surprised by the RL-17!
Every thing the same, except for the powder, the old reliable Oehler records average 15' velocity at 3333 FPS - a whopping 250 FPS gain!
The grouping was not quite as tight, opening up to 0.6" for five-shot groups - the mule deer and pronghorn didn't complain.
For most of the '09 tournament season (Hunter Class), I shot a 25x47 LAPUA, using H-4007, which shot rather well - competitively that is. I never got around to chronographing the 25x47, but of note, it shot the smallest AGGs with H-4350, RL-17, and H-4007, all at the same charge weight!
But, the H-4007 was the 'AGG Winner', so I used it all summer. Oh, all showed 'pressure' symptoms at about the same charge weights - via the BAT actioned HBR rig, 'pressure' is when the bolt-lift becomes noticibly 'sticky'. In none of my 'testing', in several cartridges, did I get the best AGGING using the RL-17 . . .sometimes, respectable, but never clearly, 'THE BEST'.
RG