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I have heard that tankbustas are good at the job, but I can't see why, mainly because I do not own the codex yet. I'm thinking of Zzapp guns on big gunz squads or Killa Kans.
Tank bustas can be ok if you have alot of AV 14. Power Klaws get the job done though. If it's AV 13 or less go with lootas, lots of high strength shots. Picking up the codex will certainly help you out.
Lootas work very well against anything short of AV13 thanks to S7 and tons of shots.
Anything 'arder than than needs special attention. Zzap Gunz and the SAG are unreliable, Tankbustas are easily distracted and fragile, and Deff Koptaz/Buggies are easy kills. I like PKs for the majority of ==My== vehicle smashing, they can handle anything the Orks go up against.
Codex would definitely help.
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