A lot of the old BP cartridges had cannelures at the bullet base. I read somewhere that in the days of more manual manufacturing, they provided the bullet stop, but I also read the position of the cannelure was merely to identify specific loadings, and, sure enough, you find photos of a lot of the old copper cases with the cannelure way down near the head, where no bullet would go.
The cannelure may stop bullet setback, but IME, pressure flattens them back out again, so they will need to be redone, maybe as often as every round if the pressure is great enough. But if it's the only way to keep the round safe for feeding, then go with it.
I used to have a lot of trouble with Remington-Peters 45 Auto cases failing to hold onto a bullet adequately after a couple of load cycles, so I would just scrap any I found. Their very thin necks (0.010") were work hardening to the point of being springy almost immediately, and my old Lyman carbide die just didn't squeeze them small enough to overcome that. I might get two reloads out of them before my fingers could push in or pull bullets out of them easily. But after I got my Dillon Square Deal B, that seemed to stop happening. Apparently, Dillon sizes its dies to err on the small side. It makes sense, as you don't want problems happening in the middle of a progressive load cycle, where you won't notice the difference in seating effort and they might escape the loader's inspection. The R-P cases did, however, start splitting earlier than my Winchester and Starline brass, so, as expected, the work hardening was exacerbated.
My point in mentioning all that is it might prove the A-MERC cases or other loose ones could be made to work using Dillon dies, and it might also overcome the need to use a cannelure to stop bullet setback with a slick bullet. A bit harder on the brass, but so is the cannelure going to be.