I've got a box of once fired (by me) 5.56x45 NATO brass, approx. 600 rounds. This is the military version of the .223 Remington, and the dimensions are the same, however the case walls are thicker on 5.56 ammunition resulting in higher pressures... It is all boxer primed, reloadable cases, and does have a primer crimp. These were bulk deals I bought from Cheaper Than Dirt a year or so ago, and was M855 if I remember correctly (if it wasn't, then it was M193). I bought 1000 rounds of it, but after losing some, giving a little to a friend in need, and loading myself, I believe I have at least 600 rounds left - probably more. It is Norinco brand, if I remember, and is decently clean brass, and will require a very minimal amount of tumbling/cleaning, IF you do that - they're plenty clean enough to load as-is. I am selling these because I have to do my primer pocket reaming and stuff by hand, and I just don't have time to do all these, plus I generally only use Hornady and Nosler brass in my .223's. I have loaded 20 - 30 of these rounds before, testing a new powder, and had no issues. The necks appear to have been annealed properly, and should make someone some great plinking ammo. For price, make me an offer. I will also do trades on other brass, bullets, primers, reloading tools, etc... Keep in mind that this box is rather heavy, and will probably cost $8 or so to ship. E-mail me or PM me for offers.