How does warranty differ on new vs. used airguns?

New airguns from authorized dealers come with the manufacturer's warranty (typically 1 year, sometimes lifetime on premium European brands), and the warranty is honored only with proof of purchase.

Used airguns may or may not transfer; some manufacturers (Air Arms, Daystate) honor warranty by serial number to subsequent owners, others do not. Modifications usually void warranty. Buying used means budgeting for possible repair (a complete reseal is typically $100 to $250 plus shipping), so price the gun accordingly.