The Sandman Rail Rifle was developed by Cadmus as a silent ballistic munition delivery system. This system propells rails via magnetic propulsion. A side effect of this method is that the mechanisim is silent aside from projectiles breaking the sound berrier (which is far easier with the Magnetic propulsion system).
The Mk I is a simple Railgun
The Mk II has incorporated Rifiling and a Targeting Scope.
The Mk III Carries over the advances of the Mk II additonally rails fired from the Mk III break the sound berrier while still in the lock and the sonic boom is absorbed into the stock. This results in a silenced supersonic weapon.
Cadmus has also developed Kryptonite rounds to use in the Sandman in respsonse to the sudden appearance of 100,000 Kryptonians in Antarctica. Kryptonite how ever is a very rare mineral and these rounds have a very limited availibility.
Mk III Sandman Rail Rifle- Variable Load, Subtle, Ranged, Improved Aim, Improved Critical, Damage 6
Kryptonite Rail- Limited Availibility (No More than 2 per encounter), Subtle, Ranged, Improved Aim, Improved Critical, Damage, Ignores Kryptonian Resistances 6
Kryptonite Aerosol Rail- Limited availibility (No more than 2 per encounter), Subtle, Ranged, Cloud Area, Affliction (Impared/Stunned/Incapacitated), Ignores Kryptonian resistances