The first POS bash I was able to help on was a few months back. I had a slightly gimped (due to my skills) sniper Apoc BS that could reach out and touch someone at about 140km. I don't even remember the system or situation, but all the cool kids were fleeting up to go kill a POS, so hey, I'm in! I think there was only about 20 of us, but we circled the wagon/command ships and slowly ground down all the indicated turrets and arrays and then banged away at the shield until the tower went into reinforced.
Different tactics and rules, to be sure. Orbit the CC repping ships to stay in range of their remote services. Pound and blast and shoot until you run out of cap, and then click the little button thingy on the fleet window that politely asks for cap recharge so you can keep shooting. Keep an eye on your shields/armour so you can ask/beg/SCREAM for repairs once the station guns get a hold of your shiny metal
I'd read some info about POSs on the fora and in blogs, but up close and personal, the POS was still pretty damn cool and all the stuff going on was a little daunting as far as information processing was concerned. Take the guns and arrays down to structure and then they get almost infinitely hard to kill, so stop shooting - check. After the defences are down, take the tower's shield down to 25% shields, and then stop til it comes out of reinforced - check. Uhhh . . . and we know the tower is in reinforced mode for "X" amount of time because . . . ?? Oh yeah, the little words beside the tower - check! :D . . . and the reinforced mode ends because all the strontinatercalthradoozleinium (or whatever . . ) runs out. Gotcha. Ok, back we go in 37 hours and 9 minutes. Aces! :)
Unfortunately for me, 37 hours and 8 minutes later, life happened and I had to do some real life stuff. Therefore, I never got to go back and apply sudden, impending, gradual, slow doom to the tower and remaining bits and pieces anchored about the POS area. No problem. Bit of a let down, but hey, I still shot at just about everything so I'll still get some "phat creds" on the killboardz after the POS is finally down, right? :D What do you mean, "no"?!?! I have to be there shooting at it at the time of the kill?? Whatever!!! And then, depression set in . .
Killmails are a fickle beast it seems, especially with POS bashery. Even the fact that if either you or the thing you are shooting at ends up on the other side of a warp gate before the kill shot lands, means you are off the kill mail. So much for pumping up my killboard stats and ratios and percentages and all that other cool stuff that the cool guys can quote. Meh. Well, another time. I'm sure there will be ample other opportunities for me to boost my stats to point out the obvious fact that the next time a raging silo, or a hyper-dangerous small ship assembly array ever crosses my path, it will have, at best, a 53.7% chance of survival. Hell yeah!
The Point? POS bashes can be fairly easy km whoring if a) you have a boat with good range, and 2) you don't get counter-attacked while bashing, and maybe c) if you are around when the POS comes out of reinforcement. Not the most exciting pvp though.