Having a couple of options is your best bet. Padlock and chain is one, a U-lock and large cable is another. It forces the thief to need more than one cutting agent.

BTW, the old master lock didn't "withstand" the rifle shot. Rather, it penetrated the lock, through and through. But the lock didn't open (and as my uncle pointed out, it never would again after that).

Great Super Bowl Ad - Shot Lock from Master Lock - YouTube

It occurs to me that thieves might be less interested in bicycles that have no wheels. Maybe not high dollar bikes though...