super: Irvine has either the most damaging limit or the 2nd most damaging limit in the game, depending on how good you are with Zell. You can empty ~60-80 Fast Shots given enough time with him.... it's even better when Meltdown is in effect, but even when it's not, I'd be surprised if it wasn't awesome anyway.
The stat topic has less respect for Fast Shot than you. Even at Crisis Level 4, it's listed as 46 shots and does 7820 damage. Using your figure of 70 it does 11900, not even his strongest limit (although it is the strongest storebought). By comparison...
Squall at CLv 4 = 8 Renzokuken hits + Rough Divide is ~11500. If Lionheart goes off (~25%), this becomes ~80k
Zell at CLv 4 = Assuming 3 hits per second = ~19000
Rinoa at CLv 4 = Wishing Star, ~49000
Quistic at CLv4 = 11800 [disclaimer about actually getting this applies]
At crisis level below 4, Irvine loses more than any other PC save Rinoa, so Squall pulls clearly past him in particular (Squall only loses 1 Renzokuken hit per level). In other words, he's always third at best, and the others aren't limited by 1-2 uses before needing to restock inventory (so he deserves all the in-game contempt he gets, there's a reason he and Selphie basically tied for lowest score in Meeple's in-game use thread). If you don't have mad button-mashing skillz, then Irvine's damage falls to meagre levels, and is in fact the lowest of any PC in the stat topic save Selphie.