Baron buff seem IRELEVANT .
For 8.4 we concluded we should be increasing the amount of damage Baron Buff gives to Cannon minions, since at present their DAMAGE contribution's often IRRELEVANT. At the same time however we also ended up fixing a bug where Cannon minions weren't PROPERLY considering their total AD in some circumstances (most RELEVANT: Banner of Command buff). That meant a situation where what was INTENDED to be a MODERATE damage increase became a massive damage increase when the two effects multiplied each other. We've got some TWEAKS going in for 8.4 as a result so that the EXTRA damage Cannon minions offer is increased as originally intended by a MODERATE rather than enormous amount.
https://i.imgur.com/8LJ0eMb.gifhttps://i.imgur.com/8LJ0eMb.gif
and it give 100 extra damage + 100 armor and magic resist . You get a 189 damage x 2 against turret .