You may use any brand or type of lock to secure your firearm case, including TSA-recognized locks. Bringing an unloaded firearm with accessible ammunition to the security checkpoint carries the same civil penalty/fine as bringing a loaded firearm to the checkpoint.

No, you are not required to use TSA-approved locks for firearms; in fact, federal regulations and TSA guidelines explicitly state that the passenger should use a lock for which only they retain the key or combination. Unlike standard luggage, where TSA-recognized locks are preferred so agents can open them with a master key, firearm cases must be secured in a locked, hard-sided container that cannot be easily pried open. TSA policy (49 CFR 1540.111) stipulates that once a firearm is declared and inspected at the ticket counter, it is to be locked by the passenger. If the TSA needs to inspect the case further after you have checked it, they are supposed to contact you to provide the key or combination. Using a standard, high-quality non-TSA lock is actually considered a best practice by many firearm owners to ensure that only the owner has access to the weapon, thereby preventing unauthorized tampering or theft during the transit process.