My 2 Issues for Gangplank

If I max my Q and shoot a barrel and I have statik shiv, since the barrel applies the damage and the crit cause it applies the damage of the crit, plus it ignores armor, shouldn't that kill minions? Im fine with it not being able to, but still, this seems a little absurd to me.. if the barrel ignores armor, but applies the damage you do to make it explode, then having a BF Sword, and a Pickaxe, plus Statik Shiv.. you Parrrley the barrel, why doesn't that kill a minion wave if it crits, the barrel also ignores armor. I just, I don't understand what I am doing wrong.

My second issue is it is way too easy for a Ranged Champion to negate Gangplanks E, one shot and the barrel dies and there is literally nothing you can do about it, you either waste your milisecond windup for Parrley to shoot the barrel and get nothing out of it cause of how stupidly weak the barrels are unless a champion is melee. Also the barrel description makes them look really strong, but they're actually weak sauce against minion waves.