Bars are certainly an options, however they are somewhat ineffective for their cost. they could get some passive boost with rangers and paras like bren cmd, but triple bar would be then particurally broken.
I consider BARs trash as far as upgrades go. You have to have 2 of them to really see any difference in the combat preformace of the sqaud using them but they're all you get unless going with Paras or Rangers. Brens are trash too but they don't cost that much so it's not as big a deal. At 90 munitions for two it's not so bad. Individually, one BAR for 60 munis and one Bren for 45 munis, they are utter trash compared to an LMG42s, Stgs, LMG34s ect.