Accuracy should be good, probably better than off the lands when using boolits. Pressure should be OK with indicated load. Biggest concern is extracting live round and leaving bullet stuck in chamber, dumping powder inside action and rendering rifle out of action until bullet removed. It is unlikely that another round would chamber with a bullet stuck in throat but I suppose a real hammer mechanic could manage to load another round so two bullets were in front of the case. THAT would cause serious, maybe catastrophic problems if fired. Snugly into rifling GOOD, stuck in rifling on extraction, not so much. Breech seating in single shots is a whole other discussion.