If there side locks, stay away from sabots, they just aren't right for the barrel twist and will go every which a way compaired to round balls. If they are just go with patched round balls and use 1/2 charge of 45-50 grains of FFF,,,remember by VOLUME,,,,NOT WEIGHT,,,Very Important!!!! Myself I use a CVA copper pistol flask with the lever and a larger spout on it(there interchangeable for different charges) and that is plenty of powder for around 20 shots plus there just a handy size and work well. Most good hunting loads for most all the side locks are from 90-100 grains and 110 would be max IMO for them. The least I've ever used was 35 grains in a 50 and it just barley "poops" them out and only good for about 50 m,,anything less it may not clear the barrel, can't say for sure. I use the Buffalo Bullets called "Balletts" in my CVA side locks, it eliminates the patch and that's what I've gotten my best accuracy with after trying just about everything else on the market.. They have a felt pre lubed wad that goes in first, then the bullet. there basically a wadcutter with a round nose, but MAN do they ever shoot straight!! Very consistent. Stay away from the 350+ gr projectiles too,I havent' found them to be all that accurate and the "Balletts" are much better and have plenty of wallop to get the job done. I love them. That is the very best thing to use from my experiences with side locks and they have put a deer in the freezer for me consistently for years. I have an old CVA side lock that I think just can't miss, just about ever deer in the last 10 years have all been head shots and many above 100M,this damn thing will shoot < than 1' MOA groups all day long, it's amazing.
One thing you might want to check though,, back in the 90's CVA had a batch of bad barrels so you might want to go to there sight and find out what serial number ranges were affected,96-xxxxx or something like that seems to stick in my mind but check first,as I can't really say for sure that is the correct number sequence. There were allot of barrel failures in what ever SN range was effected, so be careful. Check first.