I have a nice older GPR in 54 as well. It’s won its fair share of woodswalks and taken many deer for me. My load is as follows, .016 patch, 530 roundball and 40 grains of Goex fff… that’s for the woods walk, I adjust the powder to 70 grains for deer hunting. It’s a very well made rifle and carry’s the patina of many years in the woods. My only complaint about this old girl is that it’s so heavy, weighing in at just under 9lbs can make it a chore dragging it around the woodswalk or for a long walk to the stand. I’m retiring this rifle as of this year for deer hunting. I’ve recently purchased a kibler Woodsrunner and will be using that for my go-to rifle.