(this is my lore not official)

a Compact yet ammo lacking Pistol created for the higher up Metrocops
How it got into Russel is hands is unknown (possibly stolen from a cop that got killed)

its a C96-Magfed all the way from WW1 modified to fire experimental High Powered Proton beams that when hitting the body causes burning
due to the small mag
Mags come in packs of 4

This pistol is personally used by Wallace Breen quite a lot but after the event of HL:A decided to not use it after the combine weaponry was changed to include the SMG, AR2 and Pistol

this pistol is truly a relic of the Combine empire is beginnings on earth