I love all the comments and agree, the MK48 is not overpowered. It does what it was designed to do. You can't run fast with it or ADS fast, It is a very slow and cumbersome gun so it will lose in a close quarters gun fight most of the time, but what it does do great is long range multi-kills. I try to run as many diverse classes as possible from quick light and fast classes to slow campy class like the MK48 with trophies and claymores. This and the LSAT are my favorite guns on the right maps for holding down a position.
I've just started using the LMG's for a change of scenery, I have a gold LSAT and am now working on the MK48, based on your info, I might try it with a silencer
* I only use them to spam objectives in dem & dom
I really hope that Ghost has these guns in it to avoid people saying anything is OP