The 58 cal Green Mountain barrel shoots great. Mine is also mounted on a Renegade. I've used .018 and .020 patches with the .570 round ball and 90 to 100 grains ffg. The 90 grain load make a real nice range load but everything I put in it is accurate and I only shoot 100 yards. Swampman's fffg should be equally accurate with the load he develops. Makes a fine rifle for target and hunting.