Hi warder,
I have used Bullseye in .38 Special, .357 Magnum [target loads], ,41 Magnum [target], .44 Russian, .44 Colt, .44 Special, .44 Magnum [target], .45 ACP, .45 Auto Rim, and .45 Long Colt since 1990.
Never had a problem. The issue of "case sensitivity" as I think I have heard it called [the condition whereby small lots of fast powder do not fill the case well] has never been a problem. Also the issue of secondary detonation has been disproven in labratory tests as well.
The danger of a fast powder, such as Bullseye in a large case, such as the .45 Long Colt is that of a double charge. But then I try to always be careful in any load and check every single case-load of powder before I seat the bullet.
I am confident that Bullseye will work for cleanliness in my .45 Schofield loads and it will be safe. It may or may not be exceptionally accurate but in my topbreaks I only need "minute-of-steel-plate" since the loads are for Cowboy Action Shooting only.
Good luck.