All use the same diameter jacketed bullet. Remington used the 240 grain soft point for .444 Marlin. Same one used in 44mag. The only bullet that was specifically designed for 444 in the early days was the Hornady 265 grain flat point. I used some of those now discontinued factory loads on deer years ago-pulled the rug right out from under them. That bullet still, or was, available from Hornady-if you can find them.

I wouldn’t waste jacketed bullets on 44spl but I do load Remington .430 jhp’s in the mag (my Classic Hunter likes Federal brass). Deer are found within 50 or so yards from the shot.

I have found most, if not all, 44 cal jacketed bullets to be .430 in diameter across the board.