10 mm round

[yak'em-n-stack'em]

If you plan on using it a lot I say just go with the .40 sw round. Simply because of price.

10mm is only a little bigger but is much more pricey and has a lot more kick.

But if you got money why not. Just depends on what you plan to do. I wanted to get a little riffle that shoots .17hmr. But the price difference between it and a .22 for gun and rounds was just too much for just bs ing around ya know