red - I picked up a couple of posts from the Cowboy Action Shooting Forum that may be of interest.
You are using 2f Swiss bp - this guy uses Elephant 3f. This is what I found from march, 2007:
"Hi all, I just picked up an old Browning B92 chambered for 44 mag, and dutifully tried a bunch of different smokeless loads I had laying around. Nothing worked worth a darn! So, I dug out a coffee can full of #429421 Keith bullets, lubed them up with my homemade BP lube in the lube groove and also the crimp groove. Seated them over a 1/8" compressed charge of Elephant FFFg, lit with a Win mag pistol primer, and they worked great! It's no problem to break clay birds at 100 yards, and I was getting 25 or so shots between wiping the bore. Aah, much better. I guess no matter what the caliber of an 1892, it's just happier burning charcoal!
Intresting, my Rossi 92 shoots high with any smokless load but dead on with Goex and a 200gr bullet. By the way you duplicate the original 44-40 exactley with 44mag brass and a 200gr bullet."
Maybe you should consider using a 3f powder - that is better for revolver cartridges. I always thought the 2f and f were for rifles. HTH. Mikey.