I don't know the gun, but I can pipe up in support of your choice of 54 cal. Deer probably won't know the difference from a 50, but if you move up in animal size with PRB's I think YOU will notice a difference.
Just for frame of reference, my 1:66 twist GPR 54's both dislike Ballets, but do fine with the 300 grain REAL bullets I cast from pure lead. They both choke on the 380 grain REALs though.
None of them are needed for deer, but it's still kinda fun to try whacking targets and such at longer ranges. The PRB gets pretty weird way out there, but if a conical is stabilized, it is accurate enough at long range to be fun. My favorite long range target is an open 5-gallon bucket full of water. Sure makes a geyser when hit, even at 300 yards. Tape over the holes with duct tape, dip the bucket back into the creek for a refill, then go back to shooting. Even if you take half a dozen buckets with you and shoot next to a creek, you are going to get lots of walking keeping those suckers full.
Call it muzzleloader golf if you string them out 200-300 yards apart along the creek, then move up each time you hit one, repair and fill, and shoot from there at the next one. It'll keep you hiking up and down the creek all day long! And beats heck out of chasing that stupid little white ball!
