The general rule of thumb is.. a hollow based conical gets no bore button, a flat based conical does.. The Great Plains are hollow base, so I would not use a bore button or patch under them. When you fire, the base will flare and give you the seal you want. Some people do fill the hollow base with bore butter. Why, I am not sure. It is supposed to protect the lead from the heat of ignition, but I thought that with the hollow base, that was the whole point..

If you can shoot sabots where you live, you might want to try 80 grains of powder and a .44 caliber 300 grain Hornady XTP bullet in a green Harvester Crushed Rib sabot. That normally is a real accurate load and a real deer killer. If you need something with more meat to it, you could got to some Gold Dot bullets..

Also, welcome to the forum. Its good to have you here.