Powerbelts arent junk, each rifle has its own perfect load. Sometimes it takes time,money and an owner with a mind thats willing to listen and learn.
I had a Winchester Apex .45 that wouldnt shoot pyrodex RS- powerbelts for crap. You know what solved it? Switching to Pyrodex P. 1" groups @ 100 yards with the 225-275 or a 385gr paper patched conical.
Simple things like that can cause a headache. Primers are another thing that can cause a huge headache. Not all primers will give you the same accuracy.
lowest shots were with 80gr Pyro p and the next top 3 ( tiny hole) were with 90gr pyro P. cva optima, 348gr aerotip @ 100 yards.
CVA Mountain stalker .50cal sidelock with open sights @ 100 yards. First 2 shots are touching. It always throws #3 but #4 group with the first 2. 348gr Aerotip, 100gr Pyro RS.
Now this is going a little overboard with bragging LOL.
CVA Plainsman FLINTLOCK. open sights, 405gr HP Powerbelt, 70gr 3f goex. 3 shots 100 yards.