I'm shooting FPBs which are full-bore copper jacketed conicals. They also seem to hang up a bit on the edge of the rifling. I had trouble starting the first few I shot, but I did not have the correct starter tip. Now I just drop the slug in and give it a good whack. I checked a couple slugs loaded this way by pushing all the way through the bore, and the bases were not torn or distorted, so I guess I don't have an issue. FPBs shoot awesome for me over 100 gr of Pyrodex. You may want to consider them.

Sabots may be another story. Cayugad has experience with sabots in this gun, as do some others. I have never heard concerns expressed over cutting or shaving sabots when loading, but maybe they will have some advise.