Works for me, and it is really most effectively used with shotgun or sniper rifle (unless you like the last-round traits) . It has a short cooldown after activating so its less noticeable with full-auto weapons. Its bug is that if the last round of your mag triggers it your weapon may seem like it jams and either takes a while to get it to finally start reloading or makes you have to switch weapons then switch back, which will give you 30 rounds in your weapon when switching back.