Most of the last batch have almost perfectly round case mouths. I have no doubt these would feed just fine. I took a few of the worst looking ones and tried them in my Ihtica 37 pump.
Holding the gun vertically, they siide into the chamber without resistance and fall right out. So this ammo is GTG in a repeater. In the past my plinking has been with SxS guns, so was not sure if they would feed.
My only concern with these wax slugs is the risk of a loose pellet on the mouth of the slug getting loose from the wax and then migrating into the action, maybe jamming the trigger or something else.
From time to time you have to add wax and more pellets to the pot. Let the pellets get hot, stirring them a bit, because they hold the heat that keeps the wax molten while it fills all the voids around the pellets in the wad.
The sealing wax is very hard, so if there is solid wax covering the pellets, they are secure. Wax contracts a lot when it cools, so I suggest filling the wad only to the bottom edge of the folded over shell. This is about where the original crimp was. Then fill the balance of the shell - about 1/10th of an inch, with a dollop of wax.
When the wax cools, this covering layer will pull back into the slug, but the top layer of the slug should still be solid wax.