I found this Chuck Hawks take on the Powerbelt bullets.
http://www.chuckhawks.com/powerbelt_bullets.htmI am aware of the negative feedback from hunters. I load them in my kids muzzleloaders because the .45 is using 75gr(one 50gr and one 50gr snapped in 1/2) of pellets and the .50 is using 80grs (one 50gr and one 30gr). So, velocities should be down enough to allow proper expansion.. I say, "Should be!" Haven't had a chance to see real world performance yet. And I've not been able to find MZ Expanders in any of my local shops.
I have shot TC sabots, Buffulo Sabots, and Hornady xtp sabots out of the .45. Nothing shoots as well for us on paper as the PowerBelts.
The .45 cal Hornady XTP sabots are actually a .357 bullet in a special sabot, not a .40 cal.. They came with a 58 gr XTP hollow point. When my daughter was real little, this Hornady XTP with two 30gr bp pellets had non existent recoil.
The kids are now quite capable at shooting bullet/powder combinations that a quite more capable.