IMR4198 is used by a lot of cast bullet shooters, loads are in many of the manuals. I haven't seen it as often in the equipment lists for the past years. I've never used any of the H powders (4198,4831, etc) just to keep the number of variables down.
I used IMR4198 in my wife's 222 Rem, and have tried it in cast bullet guns from 22 Hornet to 45/70. I gave up some years back, and was able to get most guns to shoot cast bullets well with Unique, AA#9, IMR4227, SR4759, etc. Also, IMR4198 must be dribbled, it goes through the measures poorly. It has never proven the “best” powder for accuracy in any gun.
Talking to some guys at the range who are very sick of me babbling about my M54 30 WCF and how I can't get it to shoot well, George H. suggested I try IMR4198. I suspect he just wanted me to shut up. You're not alone.
Willing to take any advice, I started with that powder, and have shot with IMR4198 and 311299, 314299 and 31141 for the past few Wednesdays.
Particularly with 31141 it shoots quite a bit better than the other powders used to date, with many groups under an inch and five group averages at 100 yards starting with 1.0 and 1.1. This, in the words of the Chairman, is a Great Leap Forward.
I wonder why some powders shoot way better than others, I wonder how often this happens-it's happened to me several times-, and I wonder if the accuracy search protocol shouldn't be modified to include many different powders.
joe b.