Had one lay'n here, . . . a Kirst Konversion, . . and the calipers handy,....
Pietta cylinder length 2.025 in. Diameter 1.625 in.
That may not be exact, . . Enuf for a machinist, . . but should do for leather work, . . .
Uberti cylinders are a just a little longer. I furget just how much bit it ain't very much.