Welcome to Librarium Online!
Main Part: Most tanks/skimmers are all weak armoured BEHIND THEM! So if you get behind them with a Purgation squad, (get them in a LR/LRC and move the heck out), and book, ded, cuz the most armoured tank is the SM/DH Land Raiders. Which then you get melta bombs/ maybe hammerhand if your fighting Black Templars. (I hate there god damn vows). And make sure that you get an amped up Henchmen with your Inquisitor Lord.
Side Note: Right now I'm thinking of getting Coteaz and using his model, and taking off his eagle and replace it with some other weapon, like maybe a master crafted something or other, (conversioned weapon).
Main Part 2: So basically, get them from behind, or else make a dreadnought go on a rampage and cleanse the damn betrayers of the godly. Cuz the dreadnought can do some serious damage to Tau, and some other races. (Had one reap through like 6 warriors) Seriously fellas, why dont you just huck the damn Psycannon Purg Squad into a LR/LRC and go for it, The LR can shoot at the tank too if the purg squad fails. And it would be better to move more units out since GKs are slow @$$'. Dont flame me with those giant termie-incinerators.
:lol: Hope this stuff helps.
A purge squad isn't that effective a anti tank weapon unfortunatly, with only Str 6 weapons you'd have to rely on your Justicar pretty heavily to hit with his melta bombs.
The problem with the purge squad as well as that is the fact that it is very very expenseive, they cost more per GK then a terminator does...
A LRC/LR with a HQ/Retinue with Shield and ThunderHammer terminators plus the LR itself is a good anti tank hunter will make a much more effective tank destorying squad and cheaper per unit (Not including the LR/GM) then said Purge squad.
Dreads are wonderful anti-Tank weapons, I always try to field two in my armies as they are just that useful plus people fear them and fire at them rather then my HQ or FA troops.
If youre trying to get behind skimmers, good luck. Theyre fast dude. They can just drive away. And all the while youre sitting with your purg squad in a tank, driving around, when they could be shooting at stuff. Plus, like what was mentioned, str. 6 is terrible against vehicles. You'd be much better off just getting a dread or somthing, cause driving around behind is not somthing the enemy will just sit there and let you do.
dreads are slow! and skimmas are easy targets if you have the right wargear.
Yes dreads are slow, but they have T/L Lascannons with which to shoot your enemies. Spending the whole game trying to "drive around behind their skimmers" is going to get you nowhere. Theyre fast (theyre skimmers for god's sake). Infact, pretty much any vehicle can get away from a land raider "getting behind it" unless you imobilize or stun it. If you were going to rush it and hop out you may as well go for the front or maybe side depending on how stupid your opponent is, because theres no way youre going to get behind them.Besides, skimmers generally dont just sit and shoot in one spot the whole game, so theyre going to be flying around anyways.
2 dreads with l/c and missile launcher, and a LR. That'll take out ne vehicle