The Barnes 325 gr Expander w/purple sabot load very hard in my .54 T/C Firehawk but they are very accurate and put a big hole in a deer..even though they load super hard I shot a huge doe one evening at 30 yds and she ran off, another big doe with her walked out of thicket and stood in exact spot, stood there while I loaded again and shot her. Took me a good 3 minutes to load due to going slow and so hard to get round down barrel..
Most times your only going to need to shoot once if you do your part so I wouldnt worry about them being stiff to load if they are accurate.