Used some Speer 250 swaged lead SWC's over 8.0 Grns of Unique. And a few of their 230 RN with that same powder charge.
The 250's burned cleaner and were far more accurate.
No leading to speak of from either.
Unique don't much care what primer you use, but I prefer the Winchester WLP's. Mostly because that's what I've used for the past few years, and have never had a problem from them.
If you're a hot rodder and like to run that type of bullet faster than what is considered normal for the 45LC, you might give some thought to lubing them with Alox before hand.
Don't know how soft Hornady's 255 gr lead bullet is, but tumbled in Lee alox and powered by a WLP primer/14 grs of HS-6 I get between 1130 to 1150 fps (due to slightly different seating depths I was trying) with good accuracy and no leading problems to speak of....Now this is Linebaugh data and not for SAA Colts! (And my Blackhawk .45 has "fat" chambers and .456" throats) Start conservative....(Oh, and new WW cases)
BTW, there a wealth of cast bullet info at the Los Angeles Silhouette Club website. Glen Fryxell is "da man" regarding all things lead projectile IMHO and may open some eyes regarding bullet hardness vs leading.....(And FWIW, Unique is not especially "kind" to plain base lead bullets...)
I have used the Speer 250gr SWC and the Remington 250gr conical flat nose factory bullet.
With both I keep the velocities down to around factory level. Oh, say about 850 or so not exceeding 900 fps.
With both I've had mixed results. Some guns shoot them beautifully, some guns just lead like crazy with them. Most of the leading comes from the Speer bullets through due to their very light coating of something Speer calls lube.
What I do with both bullets is coat them good with Lee Liquid Alox lube. That does the trick. No leading.
If these bullets were not so darn expensive I'd use them a lot more than I do.
Recently I bought a bulk pack of Hornady 255gr RNFPs and loaded some. Haven't shot them yet. Will soon.
I've heard they are good bullets.