I think you might be surprised by what a 24" barrel can do with IMR-4227 at the maximum standard pressure that would be appropriate for an 1873 Winchester or Colt Single Action revolver. IMR-4227 will likely gain nearly 400 fps in the 24" rifle versus the revolver. Of course, you want to stay within the pressure limits of the gun. It's just that IMR-4227 keeps pressure over a longer duration than faster powders. It is also more flexible than some of the other powders in that approximate burn rate, meaning it doesn't have to be loaded to as high a pressure to work well. In this regard, I am thinking of W-296 or H-110 as being unsuitable and possibly unsafe to load to the pressure limitation of an 1873 Winchester; being unstable and erratic at such low pressure, they are only suitable for true magnum pressures. But IMR-4227 doesn't suffer from that problem; it down-loads nicely. I'm not saying you can match some of that hot Buffalo Bore 44 magnum ammo by any means. But you are going to gain a substantial velocity increase by switching from a faster powder to a slower powder when loaded to the same pressure in that longer barrel.
Yeah, don't blow your gun up; be careful! But that 1873 Winchester is nothing to scoff at either. Also, handloading is not for everyone. It's inherently risky, but I've heard of bad factory ammo too.