W540 was designed as a 12ga powder for heavy shot loads,,1 1/4+.

But it was also listed in loads in the 9mmLuger, 40 & 10mm and I think the 45acp.
Not sure about the last one.

I used it some in 9mmLuger. A small amt came along with a couple flats of heavy loaded 12ga reloads loaded with it.
I knew the source of the loads and shot those up. The rest of the powder loaded quite a few 9mm for me.

**added
I should have seen muddocktor's link before posting..
It'll give you some handgun loads using W540 including 45acp.