Since you bring "balanced around PD2 LMG mechanics" i don't see how 30 round "LMG" could work in PD2. So for having much smaller magazine you gain accuracy/etc but you cant utilize it fully since you're not allowed to use sights/bipod and you end with not effective psedo-LMG. At least that how it was when i tried idea of "STK Ultimax 100 Mark 5".