After having a lot of fun with a nimble SMG tin can a couple of times, I decided to see if the combo of good power, mobility and defence could be translated to other firearms types.
It works with swords too, but that's another topic.
One problem I have with making tanky builds in Underrail is that going all-in on being a tin can ASAP often leaves you up shit creek.
The tungsten available before killing the Beast is so poor (and by poor, I mean anything under ~140 quality for practical purposes) that even if you stuff it into every orifice of your character, you end up sacrificing all of your mobility for a mediocre damage resistance that doesn't make up for the impotence of having no movement points without using Sprint and/or Contraction - and God help you if you encounter a psionic.
Past Depot A, damage threshold is useless 95% of the time without a full, high-quality tungsten suit of armour; damage resistance is king.
Consequently, I prefer builds that are able to strike hard and fast and reposition that can then comfortably slip into a suit of super steel armour late-game to boost their tankiness with up to 95% mechanical damage resistance while still retaining a good portion of their earlier mobility and hitting power.
With high-enough quality super steel, foam and boot springs, you can reach 95% damage resistance and still have around 40 natural movement points late-game
That's great and all, but becoming a tin can should be a power boost to your character, not a necessity in my opinion.
Assault rifles are a perfect complement for this role.
Though assault rifles are my least favourite weapon type in the game, I still enjoyed playing this build (especially messing around with the Ambush feat) so I figure someone else might want to try it.
The build:
https://underrail.info/build/?HggDBwMPAwfCoFAAAAAAwqA_SwAAbnNKRmkANwAAAABGORkmOxUCSiQrSUsxKEUqwrZ8wqTip4IC4qeqA-KntArfvwI didn't even bother taking the big-brain suppository until I got past Depot A because there's only one Psi ability I really wanted; Telekinetic Proxy for setting off Ambush.
You could go without Psi AIDS and just use flares and molotovs, but they don't always go where you aim them, especially with 3 DEX, so I prefer the consistency and added utility of the proxy.
Once you go for being a Psionic, you may as well get Electrokinetic Imprint and Telekinetic Grounding for their utility and you could even branch out into a bit of TM if you feel like being a shitter - I overinvested in crafting and still had plenty of points to spare, so it's easily done.
With 8 -> 10 Strength, pumping intimidation to REEEE your enemies into submission is also a possibility.
The main thing with this build is to always pump your stealth as not only is it a useful utility, but it is also one of your main sources of damage.
Before you get metal armour, therefore, black cloth and clothing like the fursuit are your best friends for getting massive critical chance in conjunction with Ambush.
As Ambush works based on your effective Stealth skill, metal armour and striders absolutely destroy its effectiveness, but even then it still gives about 40% critical chance boost when it's active, which is not too shabby on top of Recklessness, the natural critical chance of your weapon and Scrutinous if you don't quit before hitting level 30.
Anatomically Aware scopes are your best friend if you go with Critical Power, and a 9mm Chimera in your offhand will make the best use of your free Commando burst as is often the case.
I think that raising STR to 10 before reaching the veteran levels and taking Body Weight Training at level 26 instead of level 28 might be better than what I have proposed, as 13 PER is still plenty high enough, but that depends on the premium you put on mobility.
Aside from that, there's not much more to say about the build as you don't exactly need to be a genius to figure out how to do well with an AR, and I'd rather not be too prescriptive with how people set up a build.
Some of the feats I chose could easily be replaced with others according to personal preference and the fundamentals of the build would not be affected much at all.
