Above:  The M110 SAS with its night vision optic mounted (top photo).  The optic is the third generation M820 Long Range Sight made by DRS Technology Co.  The M820 converts the Leopold daytime optical sight into a night vision device.  In this photo, the KAC sound suppressor has been removed from the rifle barrel.  The M820 night vision optic attaches to the rail with throw levers. In the uppre photo, the adjustable butt plate is partially extended.  The lower photo shows the rifle with the suppressor mounted and the M820 night vision optic removed.  The butt plate is closed in this photo.  (Photo: KAC)

Below: The KAC sound suppressor is a quick attach/detach unit designed to disguise or deceive the enemy as to the location of the sniper.  It does not make the shot completely silent, but it reduces the noise signature and muzzle flash.  This makes the sniper very difficult or impossible to locate even in daylight.  The left photo shows the flash suppressor that is screwed on the end of the barrel that centers the muzzle end of the suppressor on the barrel; the right photo shows the machined end of the gas block that provides the second center for the suppressor and the notches  for the suppressor clamp that secure the suppressor to the gas block.  The suppressor clamp is the squared-off inverted U-shaped device extending from the back of the suppressor being held above the barrel.  The nut behind the gas block contains the latch for the folding front sight (that folds into the top of the RAS).  (Photos: KAC)

Above:  Attaching the KAC suppressor to the gas block of the M110 SASS.  (Photo: KAC)

Below:  The KAC supressor is latched to the gas block by the U-shaped clamp.  (Photo: KAC)

Above:  The folding front sight is erected by pushing the button in the nut.  The sight is spring loaded and locks into the raised position.  To retract it, the button is pushed-in, and the sight is pushed back into the rail until it locks in the stowed position.  The folding sights on the M110 SASS are provided for the sniper if the primary optical sight must be removed from the rifle.  The folding iron sights are a back-up to the primary optical sight in a "just in case" situation.  (Photo: KAC)

Below:  The rear folding sight can only be erected after the primary optical sight has been removed.  The rear sight is an aperture-type that is fully adjustable for windage and elevation.  The T-shaped bar below the sight is the charging or cocking handle for the rifle bolt.  (Photo: KAC)

Above: A right rear 3/4 view of the primary optical sight on the M110 SASS.  The backup rear sight is folded.  The large, offset knob on the left of the scope rear is ON-OFF switch for the lighted reticle (and contains the battery to power it).  The Leopold scope has three knobs: the right knob adjusts windage (moves the vertical crosshair left or right); the top knob adjusts elevation (moves the horizontal crosshair up or down); and the left knob adjusts parallax (or focus) of the scope.  The "bump" just below the rear scope ring is a spent case deflector for left handed shooters.  The spring-loaded cover keeps dirt and debris out of the rifle and opens whenever the bolt is cocked  or moves to the rear.  The recessed button is the magazine latch.  The recess prevents accidental release of the magazine by brush or the shooter under stress.  The RAS (rail attachment system) is composed of an upper and lower sleeve or section that allow for the atttachment of handguards and other accessories to the rifle on top or the sides or the bottom in any position desired by the sniper.  The upper part of the RAS sleeve attaches the barrel to the upper receiver and protects the gas system that attaches to the gas block.  The RAS sleeve itself does not touch the barrel at any point -- top or bottom -- and this "free-floating" of the barrel adds to the accuracy of the rifle.  (Photo: KAC)

Below:  The RAS sleeve that surrounds the barrel, but does not touch it to avoid any affect on the rifle's accuracy.  Most accessories that attach to the RAS sleeve either attach to the upper side or the lower side of the Mil-Std-1913 rails.  Some accessories also can attach to the sides of the RAS sleeve, but a set of long and short handguards attach to those unused parts of the the RAS sleeve, where needed, to protect the sniper's hand.

Above: The upper part of the RAS sleeve screws into the upper receiver and the lower part of the RAS sleeve is attached to the upper by Allen-head screws.  Here, the screw is being removed in preparation for removal of the lower RAS sleeve.  (Photo: KAC)

Below:  The lower RAS sleeve is removed from the upper RAS sleeve.  Note how the lower and upper RAS sleeves fit together to form a rigid whole around the barrel for the mounting of accessories.  Note also that the upper RAS sleeve is longer than the lower RAS sleeve.  (Photo: KAC)

Our detailed look at the M110 SASS is concluded in Part 5.