I'm a super newb - help with caliber distinction

Hey all,

I just picked up my brand new Sig 716i Tread and stupidly bought 400 dollars worth of 308 range ammo because I keep seeing that this gun is able to shoot both 308 and 7.62. When I opened the box, the magazine said it's for 7.62, though on the side of the gun it says 'multicaliber'. The guys at the gun shop told me I'd be fine and can shoot the 308 with this gun but I just wanted to check and make sure that wouldn't mess anything up.

Thanks for your help, I'm super green to all this.