User blog comment:Kogath/Monster Hunter 4 Ultimate for the Nintendo 3DS/@comment-28303251-20151004011311/@comment-5569775-20151005131700

The cannon can be very useful, IF you happen to have a set with Artillery God and you would do more damage with it than with whatever weapons you have. It also helps as its the easiest way to break multiple parts at once, assuming the others can keep him in the right spot. You can also use it to shoot him out of the air(assuming other people don't fire the cannons before then or move it to a different side).

For example, if using Black Fatalis Blade(GS) honed for attack, with a set that has Honed Blade and Challenger, and with the Power Charm/Talon, you'd have a base raw of 365(409 when Gog is enraged). If you do a fully charged overhead slash to it's weakest spots during the first stage(Belly, Neck, Front Legs, value of 40, according to Kiranico) then(assuming the 110 MV for the attack is correct) you'd do roughly 236 Damage(260 with Challenger activated) not including the Dragon damage. You'd pretty much only be able to hit those while it's knocked down and charging takes a while, which can slow the total DPS.

With the Cannon, it's better to load all the shots and then fire while it's knocked down or getting back up. If you have AG then each cannon will be doing 221 fixed damage(238 with Felyne Bombardier and AG). If all 10 hit that 2,210(2,380) damage. But it takes awhile to load the cannon and get him in position. The damage is close overall though. But with a GS with lower base attack, if it isn't honed for attack &/or if you don't have a set that gives Honed Blade/Challenger +1/2, then your DPS will be much lower and the cannon would do more.

That said, the majority of the people in the party should be on the ground, otherwise it likes to spam it's beam attack.