Timbo23 makes a valid point about light loads in a .45 Colt. Some light loads with some powders could possibly be an issue.
That's why many of us use Unique powder for such loads.
It can be loaded easily,, and give plenty of performance,, yet is also considered a "light" type of load. It's one of the very few powders that has that versatility.
Follow loads in a manual,, with a heavier bullet,, and get 900-1000 fps,, and it'll feel sweet in recoil, yet deliver a proper wallop on whatever it hits.
If you feel the need to assure a better chance of not having any pressure issues,, then find some TrailBoss,, (Hard to find but has resurfaced recently.) you can load that to a 90%-95% case capacity under the bullet without worries. Just don't overload it & compress the powder with the bullet.
Since TrailBoss is still hard to find,, I go back to Unique. MANY are the serious handgun hunters who use a load with that powder as a dependable & very capable one in big bores. And it has the benefits of milder recoil.