Yep, the Breda 30 was just bad. IMO probably one of the worst automatic weapons ever made, for reasons already described. The Breda 37 was a good weapon in most ways, and unlike the Model 30, didn't need oil to help with extraction. Problem was, one, it was heavy. Easily the heaviest rifle caliber class air cooled MG of World War II to see wide use. Speaking of caliber, it used the 8x59mm Breda MG round. Which was used by the Model 37, the Model 38 tank MG (which could be adapted for infantry use), and the Fiat Revelli 1935 (a much modified Fiat Revelli 1914 of World War I vintage). Aside from a couple of semi auto rifle prototypes, the round was only used by Italian medium MGs.
Ironically, compared to the Model 30, the Fiat MGs mentioned didn't use oil to help with extraction. Official manuals and examinations of existing guns show no oil reservoir. However, the M35 may've used oil applied to the belted rounds, and it also used a fluted chamber (which anyone who's familiar with HK's roller locked delayed blowback rifles, MGs and SMGs will be familiar with).