If I choose extended mags it really goes crazy and will no no reloads at all. Single shot it will give me a max of 40 rounds in the clip and 41 for a reload, but when you reload, it goes no ammo.
I've tried switching out weapons, restarting the game, restart at the last checkpoint, etc. to no avail.
This troubles me as I really love the SCAR as my main weapon.