I play on PC and use steam. I've done the challenges for multiple guns and I still don't have them unlocked. I've beaten both Bullet Storm 1 & 2 and have unlocked the KTS100 MK8 but for some reason I don't have the M240L unlocked and can't even customize the M240L Gilded Storm build that I unlocked. I've also completed the Close Quarters challenges both 1& 2 and I've unlocked the SL9 but can't use the SCW-10 even though I also purchased SCW-10 CAIMEN build. I've tried restarting my game a bunch of times and tried repairing the files through steam.
