I don't want to rain on anyone's parade lms
. But I'm a member of half a dozen muzzleloader forums and have seen darn few reports of good results with that bullet in modern 1:28" twist rifles. Most of the time they have been disappointing, giving nowhere near the accuracy of pistol bullets in sabots.
I hope that's not the case with your gun, and will be looking forward to a shooting report.
If they shoot well for you they should be great deer killers. The old .50 caliber 410 grain flat point conical (which has been discontinued) was a great shooter in a few of my guns and devastating on game.
If those Lees don't shoot well, and you want to stick with full bore conicals,, give the 385 grain Hornady's a try. http://www.grafs.com/retail/catalog/product/productId/6845
If you want to try sabots, I recommend you pick up a pack of the sabots in the first link below and the bullets in the second link below and give them a try over about 80 or 90 grains of powder. That combination shoots well in all of my 1:28" twist muzzelloaders and the bullet is excellent on game.