this achievement can go fuck itself...i've done it countless times on easy with both the only-minigun method and switching to the sniper rifle for the sniper part. after switching weapons sometimes I am unable to shoot. sometimes i have to hold both LT and RT and the minigun will start to shoot. Sniper rifle doesn't do anything. I have deleted the DLC and preference file and nothing helps.
Edit: tried a new save on my hdd and not cloud and eventually unlocked it. Not sure what was going on where I couldn't shoot, I was re-pumping the sniper.
Last edited by Quid Squid; 08-20-2013 at 03:10 AM.