I almost mentioned this, but I bought mine so long ago that I was afraid they might have stopped making it . . .
They work pretty well (though I find that mine is not as accurate as the .45 rounds through my particular pistol). Another alternative is to reload and back the rounds down for target practice (but not so much that they don't cycle the action!)
(Y'know, I just realized for a first-time pistol purchaser this is a bit much too fast . . . .22 conversion kits and now I'm recommending you start reloading. Gee! I sometimes forget that we got into this hobby a little bit at a time!)
I also concur on the "try before you buy" and "get some training" recommendations by wardaddy & others here . . .