I picked up a .40 S&W SigArms Mauser M2 for cheap a couple of gun shows ago. I bought a couple of extra barrels and a boat-load of magazines (CDNN has them for $3.99). I dropped off two of the barrels at my local gunsmith to have the chambers reamed to accept the 10mm cartridge (leaving one in .40 S&W) and I have removed the magazine spacer to allow the longer case of the 10mm ammunition to function properly in about half of the magazines. The pistol is built like a tank (being originally designed as a .45 platform) and the barrel is quite thick with a supported chamber, so I have no doubt the conversion will work fine. Actually, others have done the conversion before -- so I'm definitely not plowing new ground with this project. However, with the relatively short barrel -- I'm wondering which full power loads will do best, giving the most penetration and energy possible. I'm familiar with Double Tap, Cor-Bon and Buffalo Bore ammunition -- but is there anything else out there that is commercially produced that meets or exceeds the original Norma loadings? Here's a picture of another owner's successful conversion to 10mm. Definitely not the prettiest pistol out there, and somewhat an oddball with the rotating barrel -- but it was inexpensive and the conversion quite simple. Most likely, I'll use this as a truck gun -- or backwoods packer since it is not high value and should provide decent power against 2 and 4-legged predators.