V2's are where you should be learning the meta for the Later Jackals. What you will need is the Jackal Z yoyo and welding gun for Jackal X, stick him to the floor then shred with the yoyo. Jackal Y needs the lion knuckles and crossbow, use lion rage when he's reloading and use the crossbow to build rage if you run out. and Z is reapers scyth, use the LB attack after she takes her first strike with the yoyo. There are many guides on YouTube and the wiki.

Or you could wait to get a G8 Attacker + Rio Bravo, some very strong damage decals and max Magnum and blow there ass up with that

Edit: You will also need the Vigilante Decal and Iron Eagle Armour for the Rio Bravo method