Has anyone in their long years of experience ever notice a pattern in the velocity listed in the manuals to what is obtained in a TC barrel? Say like if the manual lists 2900 fps in a 24 inch test barrel the velocity that was obtained in a 15" barreled Encore. I know what I have gotten but I have only done 3 barrels. Just wondering. Slim

SlimL,
The way I would describe would be that basically you step down to the rifle performance of the next smallest case design (not always true-but close) of the case you are using in your specialty handgun. My 7.82 Patriot (similar to 300 Win mag case design)XP-100 does 3000 fps with a 150 grain pill--which is equal to a 30-06 rifle length performance. My 284 Win XP-100 shoots a 140 grain bullet at 2750 fps, which about the same performance you would get in a rifle length barrel of a 7mm-08. My 7-08 XP-100 would shoot a 140 pill at 2540 fps (proably close to 7mm-300 savage rifle performance?). I can't remember off the top of my head what my 338 Win Win Mag Encore handgun barrel did, but is was close to what a 338-06 would do in a rifle configuration. These are rules of thumb. I load for accuracy not for the fastest load I can get. Hope this helps.
xphunter

As a rule of thumb for standard bottleneck cartridges, you loose 30 fps/in from 24" down to 18", and from 18" on down, you loose 50 fps/in. This should get you +/- 50 fps. For straightwall pistol cases, they seem to be 30 fps/in on down to revolver lengths. I don't know about the newer "supermag" chamberings, but would expect that they would loose more speed per inch.