Product Overview: Telescope Mount M90 (T183)
NSN: 1240-00-344-4689
P/N: 8299670

Description
Telescope mount M90 consists, primarily, of a socket and a drive worm assembled in the mount and controlled by the cant correction knob and the adjustment worms. This device mounts on the rear bracket of the 106-mm recoilless rifle M40 (T170E1). The bore of the socket incorporated in the telescope mount is slotted, keyed, and tapered to accommodate the slotted and tapered objective end of the elbow telescope M92D (T168E1), and a round nut is provided to lock the elbow telescope in place.

Functional Description
When the cant correction knob in the telescope mount is turned right or left at least 21 degrees to either side of the midpoint of the knob's range of travel, the mount, through the combined rotations of the drive worm and the gear segment of the socket, will provide cant correction to the elbow telescope M92D. When the azimuth adjustment worm AZ is turned, it will deflect the elbow telescope reticle cross at least 11 mils to either the right or left of a vertical target line. When the elevation adjustment worm EL is turned, it will deflect the elbow telescope reticle cross at least 11 mils above or below a horizontal target line.

Tabulated Data
a. General
Length 3 11/16 inches
Width 2 9/16 inches
Height 2 15/16 inches
Weight 3 pounds

b. Mechanical Characteristics
Cant correction knob:
Range, right or left 21 degree minimum, or 3 1/2 turns
Bore sighting adjustment worms:
Azimuth, deflection right or left 11 mils minimum
Elevation, deflection up or down 11 mils minimum