Choose the "Grinder" Perk deck. You regain health when you shoot stuff. You can penetrate armor on any of the many shells you Grimms will shoot. Anything else won't serve.

Quick Fix (Aced) - Aced gives you 10% damage reduction for 2 minutes. Much better than the 5 seconds for Pain Killers. Doctor Bags (Aced) - I could write an entire essay on why Doctor Bags are better than First Aid Kits. Quick summary; First aid kits won't reset downs. Take medic bags. Trust a pro. Inspire (Aced) - Is probably the best skill in game. It will save you and your team again and again.

Stable shot (basic) - An extra point that was leftover. Stability is good for our build. Bad accuracy is good. (Yes, you read that last part correctly.)

Shotgun CBQ (Aced) & Shotgun Impact (Aced) - Reload speed and damage are great. Close by (Aced) - Hip-fire while sprinting is the entire point of this build. Larger magazines and faster firing rate are bonuses. "Far away" gives us accuracy, something which we DON'T want. We want those shotgun shells spreading everywhere and hitting everything. Overkill (Basic) - It was either get Overkill or get Frenzy (Fugitive tree). Considering all the bonuses to shotgun skills this tree is was an easy choice.

Resiliance (Aced) & Bullseye (Basic) - Probably the only points you can move around if you want to. I personally love the Flash reduction and small armor boost from Bullseye but it's up to you.

Only thing to note; if you remove the points from the Tank tree you can get upgraded drills.

Sneaky Bastard (Basic) - You'll have 4 concealment with the right mods so no need to get the aced version. Inner Pockets (Aced) - This is a matter of point optimization. The aced version doesn't provide any benefits but is still better than wasting more points than necessary in this tree. You must have both "Parkour" and "Duck and Cover" aced, while still need the basic version of Inner Pockets for concealment. This leaves you with four points left to get access to Sneaky Bastard, which means either paying an extra two points for "Dire Need" and "Shockproof" basic or just biting the bullet and taking Inner Pockets aced. Parkour (Aced) - Reload while sprinting. So now you can both fire and reload without slowing down. The sprinting in any direction is a bonus. Duck and Cover (Aced) - Essential for this build. Giving you 10% extra dodge while sprinting.

Low Blow (Basic) - 4 concealment means not needing to take the aced version. Critical for the build. (Haha.) Optical Illusions (Aced) - Essential to reduce concealment. The alternative is acing both Sneaky Bastard and Low Blow for another 14 points. D:

Messiah (Aced) - You'll be running off a lot on your own. This will save you from a sudden down in a bad spot. Swan Song (Aced) & Feign Death (Basic) - Swan Song has to be my favorite skill (besides Inspire). Gives you good control over where you go down and lets you take lots of enemies with you for free. Feign Death is just a bonus. Choosing any other path to Messiah will cost you more points. Nine Lives (Aced) - Essential skill for any build. The extra downs make a huge difference in the long run and the 50% extra bleedout will make using your Messiah skill easier.