More on the GP-100 in 10mm Auto...

For starters, this is an extremely well made gun. Very tight tolerances, including throats and bore. Probably the deciding factor in it's fine accuracy.

The 10mm Auto can be long seated to equal the 10mm Magnum with the right components. I use the Missouri Bullets 200 Grn Coated. I taper crimp over the back band. This completely eliminates bullet creep. Not an issue with coated bullets as there is no lube to deal with.

10mm Auto Long Seated on the left, 10mm Magnum on the Right.

The TK Moon Clips are .050" thick and hold all 40 S&W and 10mm .003-.005" off the recoil shield. Cartridges headspace just as a Rimmed cartridge this way.

I thought the whole package came out pretty nice...