On tier 3 You may consider taking One in the Chamber instead of Anti-Armor Shells if you play vs team that blocks or make you miss your attacks.

Mostly difference between my build and other builds is level 1 talent and eventually 10/20.

Q: Why Tazer Rounds on level 1?
A: For early game your team having additional 2 sec of slow result in much more damage dealt to a target than 20% snipe damage would deal, also once You get Anti-Armor Shells You can hit target at least 1 additional time for free resulting also in more damage dealt than with 20% snipe damage. Not to mention how good it is if someone wanna bodyblock your enemy or is late for fights etc.

In late game when You get Crippling Shot that means You and also all your teammates will have 25% bonus damage vs target for 2 bonus seconds, which is A LOT, also that way You have enough time to use Crippling shot,Snipe,Hit+ Triple Tap with 25% additional damage which is INSANE compared to that 20% Snipe damage that everyone takes.

Pro tips: You should have on mind that your Holo Decoy also use Crippling Shot,that also adds 25% bonus damage versus target!
Also if You are in situation it is very useful to use Crippling Shot on forts/keeps/core on Blackheart's Bay once cannonballs needs to land on enemy building so you add 25% damage to them. :)