Generally your warranty will run from date of original purchase to cover defects in the purchased product. If the shop doing the repair under warranty is officially authorised by the manufacturer then that warranty should be intact. If not then they're effectively invalidated whatever warranty the OEM offered and you'll be at the mercy of whatever the retailer offers as a warranty on parts and labour. In normal (non airsoft) circumstances that's usually going to be in the order of three months but in the case of airsoft I'd say it's right up to the point that you pull the trigger and use it. Then it'll be your fault if it goes wrong again because your BB's are the wrong shade of white.