I recently was able to pick up several cases of 5.56 at a good price. I have never seen NATO Stamped ammunition which was Nickeled plated Lake City brass with sealed & staked primers and a 55gr FMJ bullet with a "very" deep crimp roll. The head stamp is 06 but looks as if the ammo was make yesterday. I chronograph this against some 06 manufactured XM193 and they both gave returns within 30FPS. Now the crimp roll on this nickle plated load looks extremely deep when compared to the XM193 so my question is could private contract specify such a change for a bullet possibly to enhance fragmentation?