Both Jack and John were recruited because of the 1st Phase of Project Poseidon.
Before Restoration Edit
Rattlesnake was with I-19 Plasma caster and the Assault Mount 3.25 "Sting-Blade" and also supported the WMB2x90 AKM Chest launcher which is used for its signature power move Shadow Strike. Its platinum visor gives it optimal visual awareness in battle.
After Restoration Edit
During Project Poseidon, researches found Rattlesnakes data base in the Shatterdome Library, showing that Rattlesnake had not been salvaged yet. They had then dispatch 2 teams; one to get the jaegers pilot, and the other to fetch the Jaeger from Oblivion Bay. They had them replaced many of Rattlesnake weapons to try out a new variety of tech: Assault mounted Scythe Blades 4, S0.5 ProtoShot and its unique "Sound Zealots".
During the 2nd Kaiju War...
Final Deployment (Blighting Death) Edit
Due to both Jack and John being Marines, Rattlesnake uses Marines Mixed Martial Arts making it a very formidable fighter. They capitalize on the Jaegers speed and strength but due to caution often fire the I-19 Plasmacaster first to try to wound the Kaiju then engage it in close combat. Rattlesnake has one of the best kill counts thanks to its fighting style.
With the new technology offered druing the start of the 2nd war, Jack and John used the art of the deception to help them turn the tide of the battle. Dubbed "Soundless Strike", the Jaeger would deploy drones that are able to mimic the cries of Kaijus past and present. This is would then cause the Kaiju to let its gaurd down for a few moments, leaving an opening for the pilots to end the vile beast.