I shoot with a clean barrel and clean breach plug with every shot. I do use bore butter for storage, but every load is with the barrel totally clean of anything. When I load each morning, I swab the barrel with a windex patch and follow up with dry patches till bore is bright and Dry. Normally 2 dry patches. Same for the breech plug. 1/8" drill bit and tip cleaner after every shot. I too, shoot T-7 with Hornady 250 gr sabbots. I have found that weighting my loads vs volume ready tightens up the groups. I am shooting a Traditions Buckstalker. It takes a lot more time to do it this way, but I have decided that a person is going to get s single shot only and if another shot should be needed, then I carry a pistol for follow up. However, with this procedure, I have not needed a follow up as the bullet goes where it's told. Killed several deer and too many hogs to even count.