muzzle reference system

{{Short description|Device used in tank guns}}

{{More citations needed|date=September 2023}}

File:Main gun on Challenger 1 tank at Bovington Tank Museum.jpg is inside the metal housing on top of the thermal sleeve.]]

A muzzle reference system (MRS) is a device used on most modern tank guns and some artillery systems that measures the bending of the barrel due to heat, gravity and other issues. It normally consists of a laser device and detector mounted at the breach end of the gun, often co-located with other optics like the gunner's sight, and a mirror at the muzzle. By measuring the deflection of the barrel, corrections can be applied by the ballistic computer to correct for changes as the gun is fired.