No way on the pellets and it depends on when your carbine was made as to whether it's twist rate would be good for sabots. The origional White Mountain Carbines had a fast twist which works well with sabots but they made some with the slower 48 twist so you need to use conicals with them. Have a gunsmith check the twist rate if you do not know how.

As far as the Pyrodex pellets go they are made for inline rifles not caplocks like your WMC. That is not a big deal though the little carbine is a fine shooting weapon with loose powder and using loose powder is not hard.

Welcome to the forum we will get that rig shooting fine