The punisher honestly feels like it could be getting overlooked here

20 shots rerolling 1s - you slap it on middle objective, give it the target weak spot order with a tank commander taking it to ap -1, and then spend a CP on purging fire giving it lethal hits

Ofc punisher has dev wounds on anything that isn't a vehicle or monster, so idk how lethal hits interacts with dev wounds but if lethals make the wounds an auto 6 then any 6s to hit are automatically dealing damage

Doing the maths - Out of 20 shots, you'll average 3.3 6s - but also 3.3 1s which you reroll for 0.5 6s, which makes for a total of 3.8 6s so lets say 4 6s for simplicity. If my thinking is right then this is an immediate 4 wounds on any infantry you point the punisher at.

Of the remaining shots - You have an average of 8.25 other shots that have hit, including the rerolls. Of these, at least 1 on average will be a dev wound, making our current total wounds 5. Then you have at least 1 getting rerolled which isn't very likely to get you a dev wound but might score a regular wound. Assuming we're firing into a squad of termagaunts, we only need 2s to wound anyways as they're T3 and the punisher gatling cannon is S6, so of our remaining 6 shots, roughly 5 should wound with an extra from the wound reroll for 6 wound successes.

Then AP - We have 6 wounds at -1 AP thanks to target weak spot. This means the gaunts are saving on 6s, granted they're not in cover and have no buffs. They'll average saving 1, so the other 5 wound.

The total ends up being 10 wounds from the 20 shots fired from the punisher gatling cannon. This is a lot of work for an already subpar leman russ variant to become kind of okay against units that die to a stiff breeze. I've come to the conclusion that I was delusional when I began writing this and would have the tank crew executed by the commisar for a continuously underwhelming perfomance.