I subtracted the cost of the .22 ammo, cause that's only fair. I've been buying the Paki Berdan primed stuff for $90/250 rounds.
I'm not a fan of reloading the fluted cases, so I don't pick up HK used brass and that Paki ammo has performed flawlessly in my HK.
Anyway; 1500 rounds = 6 cans x $90 = $540. Subtract $48 for 1500 rounds of .22 ammo. That's just a bit less than $500 I guess. But add shipping to the conversion kit. It's about 1500 rounds to break even.