Yep, same bullet for all of them. The 54 cal ML uses a .50 bullet and the .50 cal ML use a 44 or 45 cal bullet.

So basically winchester only makes the two larger platinum bullets, they just use them in different delivery systems is all.

Hornady is the same way. Most of your muzzle loading bullets are just .44 or .45 cal pistol bullets in a sabot. Being over driven in my opinion. That is why I switched to the Precision Rifle bullets. Of course now that I bought a slug gun I may not get to see how they perform on deer. I know they shoot better out of my rifle though.

Winchester 20-Gauge Platinum Tip
This 23/4-inch, 20-gauge sabot round contains the same Platinum Tip bullet that Winchester loads in their .454 Casull handgun hunting ammunition. The .454 Casull may be a giant, scary handgun, but these 260-grain, .45-caliber bullets are dainty by shotgun-slug standards. Driven at 1700 fps, and far more aerodynamic than most slugs, the Platinum Tip retains velocity—and energy—extremely well. At 100 yards, it hits with as many foot-pounds as a 12-gauge Foster slug does at the same distance. You can sight these in for 100 yards and hit only 1.1 inches high at 50 yards and 2.2 inches low at 125. For a shotgun slug, this is laserlike performance. Better yet, their light weight means they won’t hit you with the fearsome recoil we slug shooters know so well.

And the same thing can be said about the 12 guage version, except it drives a .50 400 grn bullet at the same speed. So you get a bit more ooomph out of it. I also shot some winchester rifled slugs that were one ounce and listed as 1760 fps.

The 12 gauge ones I shot had no less or more recoil than any of the other slugs I shot though. keep in mind my gun weighs more than 10 lbs.

They shot pretty well out of my H&R, I would like to try some of the remingtons too. And some of the lighter rounds that go 1900 fps.

Paul