It is possible to form it from 38 special, they look weird but 38 brass is cheap.
I've only been able to lay hands on 100 pieces of starline 41 and have been on backorder a year. Have formed a couple of hundred from 38 and all have 3-4 loads of black powder so far and only split a few formed ones.
Don't know if they will ship it but buck and jakes outfitters( one in Booneville and the other in Evansville indiana) had pre covid price on 44-40 conversion kits. They never sold them and so they are still at the old price, under $75.
I purchased one during covid and got ahold of the proper powder funnel to use as a 38-40 kit when no one had one
Good luck
What caliber?
Do you need a toolhead?
Dies?
I just bought some decent priced used full conversions with dies, toolhead and powder measure from a good guy on Smith Wesson forum