Just because ....

[Peter Laidler]

Rear sight deflection is controlled by the screws being done up tight against the sight base against a clicker spring so they should never come loose (not in my experience anyway) The sight leaf is held rigid by the balls and springs on the axis pin. It is a simple job to replace the 2x springs and axis pin. So a loose leaf shouldn't be a problem either especially as if the springs do loosen up, it will do it gradually over time.