As has been suggested, SOE traded in some of NC MAXes power (without extended mags, which ALL serious MAX users have) - and boosted slugs efficiency. Not very realistic scenario tho, stationary MAXes. Someone was suggesting that Mattocks are now "OP".
But continuously firing Maxes does happen often. Slugs are just outright better atm other then it can't insta-gib infantry. kills Maxes in the same number of shots but can do it at a longer range.