"Most things" covers a lot of ground. You include rifles in the mix and while the WFN bullets whack pretty hard they are not the most stable/accurate for longer ranges. A Long Flat Nose works better for that.
Bullet fit influences cast bullet accuracy quite a bit so one bullet at one diameter would be unlikely to fit a whole bunch of different firearms unless they all have the same throat dimensions. You could get a mold to cast the largest bullet you'd need and then size it down as needed.
Long winded preface here but it ends up agreeing with the previous posters. A good 429421 or similar clone at 245-250 grains has been gittin' it done in a vast array of different handguns and rifles for many decades, no reason to stray far from that.
If you know your alloy will be constant you can contact one of several mold makers and specify the alloy and as-cast diameter you'd like and they will cut it appropriately.
Gunnery, gunnery, gunnery.
Hit the target, all else is twaddle!
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