Not for .454, but I have done a good deal of experimentation with other short barreled magnums. In some cases, trimming magnum cases to special length to work up some fairly high pressure loads. This is a really important and very overlooked aspect in reloading powerful cartridges for snubs. I still see a lot of guys that need velocity in these types of guns, like what you might need for a large game/self protection revolver like the Alaskan, but still go about it with a magnum powder like H110, 296 and others that are similar.
I stop using those types of powders once barrel length starts dipping under 6", I'd probably use 5" as the standard if that length was more common, as it should be! Under 6", I start looking at powders slightly faster and AA#9 is hard to overlook. Blue Dot used to get a lot of use for this. Going on down to barrels under 4", AA#7 starts looking real good. I've used V-V 3N37 and data is not hard to come by. At this link you'll find Ruger and TC data for .45:
http://www.accuratepowder.com/data/...olt data Ruger TC stronger pages 144 145.pdf
Shooters often bring up the velocity loss with shorter barrel issue, but this goes beyond rule of thumb. Muzzleblast and objectionable velocity loss starts creeping in here. For defense loads, it gets real relevent!
Many believe that pressure peak occurs at a given location with handgun cartridges, but if you look at the research, you find that this is a time based measurement and it is effected by burn rate of a specific powder. Lyman has a very good and detailed section on this. Powder selection is everything here! For short barrel magnums, velocity loss will be less with powders slightly faster than magnum, but I'm not talking about Unique and faster powders, although I'm sure plenty of guys go about it that way. I wouldn't jump far ahead on the burn rate chart when making a powder selection for this scenario. AA#7 will give you some great loads in cases like this. At the link I posted, you'll also notice #5 is listed.
In .454 cases, you might also want to look at Ramshot True Blue, their data used to show standard deviation for their loads and what they showed for .454 Casull was outstanding. Naturally, performance won't look as good for the long barrel lengths typically used, but when you get into short barreled magnums, things change with barrel length!
