Hickslawn, he was talking only about the actual Harvester sabot, not the projectile itself I think And it you don't use the proper loading jag for a expansion tip (plastic) bullet may well come out. The bullet are just a standard hollow point with the plastic expansion point added to aid in expansion at low velocity and to increase the BC of the bullet.
Harvester does make sabots that will hold up to the high pressure of smokeless MZ's MMP's just won't handle the higher pressure loads as a general rule. Depends on how hard you push the load and the bullet diameter in relationship to barrel bore.
What you guys may or may not know is that almost every sabot load, maybe every one, for a MZ is using either Harvester or MMP sabots, Doesn't matter what name in on the box of bullets.