The .45 colt doesn't often get the respect it deserves...in a rifle, especially the marlin, you can bump up some handloads to be pretty stout-only thing to worry about is the case strength-the marlin is hell-for-stout...I wouldn't use one past about 75yrds though, with pistol cartridge carbines, pretty much as long as your accuracy is good, your power is too (not pistol cartridges, revolver cartridges-a 9mm is accurate at 150yrds, but won't be good for deer past 35).

The .44mag is for sure a better killer, but the Marlin Cowboy isn't offered in it (ok, so it is, but the asthetics are not the same)...The .44mag is my cartridge of choice-I've got a couple 1894's and several revolvers that are awesome deer hunters-The mag bumps you out to about 100-125yrds with stout loads-as long as accuracy is good.

For brush, I'm a huge fan of a .45-70, get the Marlin Guide gun and you've got one heck of a marlin Brush buster...I've got one of the 1895 stainless guides and a Marlin 1895 Cowboy, the Guide gun is my brush rifle-even though it's accurate to 250yrds, and the Cowboy is my long range shooter.

And there in lies the rub, which do I use for brush-the .44mag or the .45-70 guide gun, they're almost the same size-one's stouter, one's lighter and lighter kicking, glad I've got TWO DEER TAGS!!!!