From Halopedia, the Halo wiki
Etilka was a modified M247H HMG employed by Jorge-052. Among his modifications included the removal of the gun shield, replaced with a heat shroud around the barrel, and the addition of yellow paint highlights around the weapon alongside more ergonomic handle placement. This weapon proved the basis of a War Games weapon, modified to fire explosive rounds and grant the wielder in the simulation increased movement speed and damage resistance. This War Games variant retained the visual look of the original weapon wielded by Jorge, with the addition of the "S-052" tag and NOBLE Team emblem. The magazine, however, now has been replaced with a red high capacity magazine.
Etilka was wielded by SPARTAN-II Jorge-052. He served with the weapon during the Battle of Fumirole and later, the Fall of Reach. During the opening stages of the fall, he employed the weapon during a mission to investigate the Visegrád Relay and later the defense of SWORD Base. Jorge would then employ the weapon during the Battle at Szurdok Ridge, using it to hold off Covenant forces so that SPARTAN-B312 could take Spire One offline. The weapon's last actions would come in Operation: UPPER CUT, with Jorge using the weapon inside the captured SDV-class heavy corvette Ardent Prayer to hold off Covenant forces. Following damage taken to the slipspace drive needed for the operation, Jorge would stay behind on the Corvette to manually detonate the engine-turned-bomb and allow B312 to escape. In the ensuing destruction of the CSO-class supercarrier Long Night of Solace, Etilka was likely destroyed.
In Halo: Reach, Etilka appears as a modified M247H machine gun wielded by Jorge-052 in the missions Winter Contingency, ONI: Sword Base, Tip of the Spear and Long Night of Solace. Aside from its unique visual properties, it displays no apparent differences from the regular M247H weapons useable by the player. Etilka is only ever seen in the hands of Jorge-052 and can not be wielded by the player. Additionally, Etilka is never named or given particular status in Halo: Reach.
Halo 5: Guardians
Etilka appears in Halo 5: Guardians as a Mythic weapon added in the Memories of Reach update. This marked the first time Etilka was given a particular name or special attributes. In Warzone, the Etilka REQ card has the following stats;
Unlike the standard M343A2 chainguns found in the game, Etilka fires explosive rounds and grants the wielder a speed boost and increased damage resistance.
Halo 5: Guardians REQ card
List of appearances