It's probably cost prohibitive now, but years ago I saw a few revolvers rechambered to smaller caliber by sleeving the chambers and bore. This was very popular with the Webley Royal Irish Constabulary (RIC) models which were .442 caliber. I saw a few chambered for .25-20 WCF in this manner, and selling for $12 ~$15. The Webley Mk IV were going for $14.95 at that time.
And some Colts were rechambered from .38 S&W to .22 L.R. in the same manner, with changing out the firing pin, of course.
I never shot one of the .25-20s, but wondered at the practical use of a snub .25-20!
Waaaaay impractical, but illustrates anything can be done.