perhaps the usual thing of the driver slipping slightly into the keyway has
happened. try pushing the flat side of your pick up against the drivers and
rotate the lock.
usually it doesn't prevent it from re-locking, but it could - alternatively if
it's masterkeyed then there could be a problem with a master pin but
that's apparently a rare thing... whatever you do, try not to force the key
in if the lock is not in it's upright position - you may end up breaking the
key pins. theoretically, if the lock is in the unlocked state, you shouldn't
be able to get the key in at all unless the bitings are in assending length
(i.e. the longest at the back and the shortest at the front)
other than that - shame on you for practicing picking on a lock that is
actually being used for security - go out and buy yourself a practice
cylinder or padlock!
