While some impressive shooting is being done with .45 caliber rifles, I would still recommend the .50 caliber. The reason for this is when shooting sabots, consider the projectile size. You have already reduced the speed of your projectile by going the muzzleloading route. This to me is not the time to reduce the size of your projectile as well. For all it is worth, projectile weight can still make a big difference in killing power.

Check your state regulations and make sure a sabot load in a .45 caliber projectile is legal. Some States require a .44 caliber or bigger. That means in a .45 caliber you must shoot a conical which might not be the best choice for your rifle.

There is really not a ballistics advantage in the .45 caliber. Granted you will get more speed out of the smaller lighter bullet, but most shots you will make are under 150 yards. There is nothing the .45 caliber can do that the .50 caliber can not do as good or better.

.45 caliber has improved a great deal in bullet selection but they still can not match the selection of a .50 caliber. Also .50 caliber are more common and easy to find. Plus they get some excellent sales on them.

There is of course the issue of hunting some day where the caliber requirements could make a difference. If all you were going to do is shoot deer, I am sure the .45 would more then get the job done. I just can not see the reason to under gun yourself with a smaller caliber.

Don't overlook the traditional rifles out there. They are just as accurate as an inline rifle no matter what people argue, and are more then able to get the job done. The problem is they are getting to be very expensive when compared to the bottom entry level inline rifles.

There are some excellent rifles out there on sale right now, and will be more of them after Christmas.. Sportsmans guide was selling a Knight Disc Elite (I believe it was) at a excellent price. A top of the line rifle.