Fortifications - Industrial - GiveMeMyFlak
This mod allows you to use Flak and Pak without CE. Some values were also rebalanced, but you can tweak them yourself with RIMMSqol or by manually editing the files.
These guns were available in 1.5 even without CE, but for some reason this is no longer the case in 1.6.
This mod is not compatible with CE.
All credit goes to the original mod's author, AOBA.
Praise be to AOBA, for their cool mods.