The SOLO mount incorporates a precise mechanical spin drift compensation for 40mm high velocity grenades. The SOLO also has a unique integral mount buffer system, which allows the operator to keep an eye on the sight and also protects the optical modules by absorbing 88% of harsh peak recoil forces.
Solo sight mount Cadex

The Solo is the backbone of the US Marine Corps HMGSS (Heavy Machine Gun Sight System).
Named the BERM (Ballistic Extended Rail Mount), it has been assigned the M520 designation.

  • Accommodates up to 4 day/night electro-optic devices.
  • Increases lethality of both 40mm and .50 cal platforms at long distance.
  • Mechanical spin drift compensation.
  • 88% absorbtion of peak recoil forces.
  • Illuminated Range Dial.
  • Customizable configurations.
Dimensions: 16.21″ x 8.64″ x 7.16″
41.17 x 21.94 x 18.2 cm
Weight: 10.45 lbs
4740 grams
Material Aluminum 6061-T6


Solo range dial Solo illuminated range dial
Solo one hand adjustment Solo rapid switch


The SOLO sight mount dramatically enhances the fighting capabilities of the soldier during day and night conditions. The system is the world’s premier military, off-the-shelf sight mounting solution. It is designed to enhance the sighting capabilities of NATO-standard weapons such as :

  • The M2 .50 cal (12.7mm) Heavy Machine gun
  • The 40mm MK19 Grenade Machine gun
  • The 40 mm Heckler & Koch Grenade Machine Gun

It converts a zone-spreading machine gun into a precise target engagement tool with one round/one hit capability at extreme distances.

The SOLO platform integrates up to three sight modules in a wide variety of configurations, and provides both day and night sight capabilities.

The system allows for a rapid switch from active to passive target acquisition mode.

During firing, the operator adjusts the range with one hand while the other is free to control the weapon. An illuminated range dial permits the operator to rapidly set the range for a quick engagement, day or night.


M2 Heavy Machine Gun
Heckler & Koch GMG

Solo interfaces

Solo – Your Sighting Solution

Solo – Mounted on the MK19 Grenade Machine Gun

Solo – Mounted on the M2 Heavy Machine Gun

Solo – Extreme Weather Testing

New Optics System enhances heavy machine guns

Fort Benning Tests New Heavy Weapon Accessories

Please see your local dealer/distributor for pricing and details.