What I use to Shotgun Jump and works great:
Settings:
Team Deathmatch
Friendly Fire: Shared
Double Health
Faster Health recover (Incase you fail at jumping the first time)
Radar Always On
Also , Care Package, Sentry Gun and Emergancy Air drop for the Higher parts to get onto.
What you do is Count to 3 and once the person counts 3 you shoot him/her in the ass.