I have the Remington BDL LH(left hand) in the 270 calibre. It is as fine a rifle as your going to find or I wouldn't been using it since 1979.
As ChesterGolf said: the difference between ADL &BDL is strickly cosmetic.
Well mostly cosmetic. The ADL doesn't have a detachable hinged floorplate. Cartridges are inserted thru the action opening on the ADL but can be inserted thru the floorplate on the BDL. Cartridges in the BDL drop out the bottom to unload but on the ADL come out the action. The BDL also has two action screws but the ADL has a third thru the front of the trigger guard that holds on the trigger guard. That screw tightened to much can change point of impact. Other than that the actions are the same.
Anyone who shoots a sabot bullet has had the problem with loading the next round with a dirty barrel we have all struggled with it.
Between muzzleloader shots I have done some research and testing on my own to find out what works for me for the next shot. I have been using a product called bore butter and when the muzzleloader is just sitting around I leave it caked in the barrel for protection. Have also found that if I lube my sabots with bore butter they really slide nicely down the barrel....