I lost 180 rounds of 556 ammo loading it into a 60 round coupled magazine. The ammo was grouped in stacks of 60 since I initially loaded ammo in smaller increments into the 60 round mag to save inventory space. It only seemed to disappear when loading all 60 rounds at once (though this may not be the case). It also disappeared when loading 60 rounds into a smaller, 40 round magazine. I lost 120 rounds before relogging to see if that would solve the issue. It did not, I lost another 60 rounds upon reentering the server.