Use the #11 caps. Pinch them to make them stay on a clean nipple. Once a cap is fired on the nipple, and leaves a bit of debris, you won't have to pinch subsequent caps. You won't like those "TIGHT" #10 caps when one of them sticks on the nipple, and you have to use needle nose pliers to pry it off- and those pliers are always either back in the shop, or at best, back at your car! :shocked2: :idunno: :surrender:
As for a load, you certainly should be able to shoot one hole groups at 30 yards with any good load. Try using 75 grains of 2Fg Goex behind that .490 ball, and a .015-.018" thick, greased, ticking patch. That load gave me a pass through broadside shot on an old Doe, breaking ribs going in and going out, while passing through both lungs, and an aorta, in between. You don't get "deader" than that, at 40 yds. She dressed out near 120 lbs. The exit wound was between 65 and 70 caliber.