Must be expensive hosing 0.43's at full auto. Must be murder on V2 mechboxes all the internals too.
At 550fps, you might as well also allow 500fps pellet guns onto the field as b/a rifles. Much more accurate and at range it'd probably be less bad than getting nailed by a 0.43 at 500fps up close.
I've heard of HK style games or games from the HotShot days with muzzle energy that'd damage gear and chip guns. Personally, I wouldn't mind playing against hot guns, but in the heat of the summer I hate full masks. I endured a couple years of oral surgery and orthodontics. I'd be pissed to get a tooth zapped for a glorified game of tag.
Want nearly free GBB gas?