Do you handload? 45 Colt factory ammo is very expensive and very weak. Boutique 45 Colt ammo is extremely expensive and very powerful.
If you don’t handload I would get either a Blackhawk with convertible cylinder or an auto in .45 ACP. There is actually a lot to like about a .45 auto besides cheaper ammo. They are flat and easy to carry and most are resistant to abuse.
If you really need magnum power in an auto, you can always look at 45 +p, 45 Super, or 10mm.
