Nova 9mm, but rechambered for the .100" longer case of the 356 TSW, using a handload, 55 grs, 2200 fps, 590 ft lbs. I smithed the Nova a lot, adding a beavertail frame tang, stippling, ambi safety, luminous sights, undercutting the trigger guard ala Firestar, adding a fingerrest to the mag, ala PPK, and moving the mag catch to the bottom, like a Ruger .22. Top rear of slide is slashed, like a Detonics, all corners are severly rounded off, Lexan grips were made for it. It's about a $3000 pistol, but it's the same size and wt of a steel Chief's .38 snub, with twice the power,and controlability, and it lays a lot 'flatter" in the Kydex front pants pocket rig. It's also a lot easier to carry spare ammo for, and 3x as fast to reload. The high velocity of this load, and the solid tin cast bullet make it AP, and at impact, it breaks into 3 segments. So it is one mean mutha, for a pocket gun.