Up to this point, I haven't wanted to order a bunch of M855/SS109 online to get it cheap, because of my preferences. I got 100 rounds, though, at a local gunshop for $62.00 out the door - just to have three mags full in my kit. The 20 rounder in the M4gery will have alternating M193 and M855 rounds. Not cheap, but not too bad for a LGS price for new USGI M855. (the stuff I got at the LGS current issue Lake City M855).