Mike.
Keep working with the Big .50. the group you shot for your review will do the same at 200 or beyond.
Here is what mine has done at 200 yards with 12 shots with a sight correction, but I must say, my .50 is a different beast. Calamity has a 1/22 ROT and it is just a couple oz. short of 14# and I use a 720 grain bullet with 110 grains of 2F powder.
I haven't shot this rifle since Goex discontinued the Express powder but I will start load development again using 1 to 3Fg Olde Eynsford powder maybe yet this summer. The .50 has always been my go to rifle for long range shooting when the conditions where rough. It will hold it's own against any caliber, but you must be able to tolerate the recoil and it will serve you well.
Kurt