why do gp bareels have total armor pen and bonus damage?

and cost no mana. May I get the reason? 1 barell does 700 damage and I have 180 armor. reduce their early game damage at least. keep the late game damage but please reduce his early game damage with these barells. his barell q combo is quite practically impossible to dodge he he timed it right. he has a qss every 10 seconds. global ultimate. and a ranged attack that counters as mele. I mean there is so much power in every single one of his abilities. I know that lcs isn't the reality for most of us that play the game but if a champion is banned or picked the most of any other one it really means something.

I mean your giving an ability that is basically an aoe crit bonus damage spell blade trinity force proc ARMOR PEN?. imagine if ezreals Q critted and has armor pen. does ezreal q cri? no. gangplank q. it does. and it still procs trinity force

think about it for a second. his q crits. has bonus damage on top of it. procs trinity force on top of it. has armor pen and more bonus damage from the barells on top of it. how much can you put in there?

the damage is just too much. it chuncks squishies and tanks and its costless as far as hes concerned.

idk can you give him flat armor pen on them and make them cost some mana. or make it not proc trinity force but still crit. or make it proc trinity force but NOT crit. it has to be one way or the other. or just remove the slow from the barells. the most overloaded single ability in the game