The furthest I've taken game with a muzzleloader is a doe at 338 yards with a 200 Shockwave over 110gr 777. I target shoot with that bullet to 400 yards but the energy is getting really questionable out there, and certainly shooting at deer beyond 400 yards with it is out of the questions. I'm of the opinion that as of 2008 the 200 SW was the best all-around bullet for long range ML shooting.
Hornady may have changed that. This year they released the FTX bullets in bulk and I selected the .458 325gr FTX for testing. While velocity is lower (1900 fps with 130gr 777 vs 2050 fps with the 200SW and 110gr 777) energy is double, even at extended ranges, and the actual (shooting-derived) BC is .21 instead of .17.
While I've heard some early reports that they are harder than the SWs and may not expand well, I am going to give them a go this year and see for myself. I'd verified that this load duplicated the trajectory of my 200 SW load out through 300 yards, so I ran the numbers through JBM to get a dope for 500 yards and shot this target yesterday. By the time I assembled a 15-foot tall holder to get the target over corn and terrain I only had a few minutes to shoot, so there was no barrel cooling and I was firing as fast as I could load the 4 shots. It was 90 degrees and I couldn't hold the barrel at the end.
This is not a cutting edge smokeless gun, just a thumbhole Omega that I have accurized (float, pillars, and epoxy bedded). I know it starts to pull left when it gets hot so I think my first two shots are the one just low of the bull and the last two are to the left but I don't know for sure. I'd wanted to get a 6-inch group but I'll take 8.5 inches with no cooling: