A mount for attaching a device to a firearm includes a longitudinal base adapted to carry the device to be mounted. The base has a track extending along a portion of the length thereof and a block is slidably mounted in the track. The block is biased toward the front end of the base by a spring. The...http://www.google.com/patents/US4580362?utm_source=gb-gplus-sharePatent US4580362 - Mount for attaching a device to a firearm
