The Leigh copper bullet I must admit interests me also. I always was a fan of the Barnes Copper bullets. The testing I did with them and a Black Diamond XR was to say the least spectacular in the devastation department and the hold together and deform perfect department. One reason I hunted for years with my Knight LK rifle and a Barnes MZ Expander. I just wish the deer had cooperated.

Are these new copper bullets heavy weight or light weight? I will be watching for your updates on it.

As for your topic of center fire VS muzzleloader, I have had deer drop in their tracks from Center Fires. Both the 30-06 and the 7mm Remington Magnum has planted a lot of deer. But it was all shot placement. I used to do a lot of neck shooting when young. But as the distances got longer, I changed to center mass shooting. Although I have still dropped them there too.

With a muzzleloader, I have never taken a deer yet with a sabot. Every time I hunt with one, I never see anything to shoot. But I have shot a large number of deer with round ball, and conical. And most of them were a bang flop.