I had a Model 27 converted years ago. Bain and Davis did the work. The cartridge is, of course, a .44 Mag necked down to .357, and is easy to load for. The last loads I did were with H110, and a Speer bullet.
They just bored out the cylinder to take the cartridge. I was getting over 1650 fps with a 158 grain JSP. The barrel was 6 inches. I still have the gun, but don't shoot it a lot anymore. I used it for metallic silhouette.