I can't say I'm much of an experimenter when it comes to builds; although I came up with this one by myself, I later found out that it was quite similar to other peoples' ideas for a versatility SMG build. I think this one is different (and good) enough to warrant its own mention, however. The most important aspect of the build is not bothering to get Per up to 6, as I don't think that the gun feats available at this level are worth the investment when the humble burst is all you really need.
Here's a link to it:
https://underrail.info/build/?HggQBwMDAwZQwqAAwqAAAAAABi0AeB5fLEYAAABGAABaK08ZJA0VNz7Co0kWRVESwofCsyrCiOKgigXip6oD4qi7A-K1rgTfvwThe amount of skill points I've distributed is influenced by my personal preference, and is what I would roughly consider the minimum for this build. I don't ever really bother using workbenches or hypercerebrix for crafting, mind you.
Some important things to note about the build (why I think it's pretty good), starting with the downsides:
-Low range with your offensive options, though this will be mitigated more and more by mobility as you progress
-You won't be seeing traps until you're a high enough level for them to not be too much of a problem
-Poor stealth ability due to use of boot spring and metal armour. Early game you'll probably be using a tactical vest and tabi boots anyway, but swapping your striders out for some good-quality ninja tabi will actually allow you to sneak quite well without too much investment in stealth as armour sloping and nimble lead to only moderate armour penalty.
-Your accuracy with guns will be abysmal in the early game due to low perception/low effective guns skill from versatility. Now that Gerhard Page drops the commando belt, getting it should be a priority if you want to take versatility earlier than I have suggested. Bullet strap belt is the other, obvious good choice of belt. Otherwise, use dirty kick/a taser to stun enemies in order to burst them down with high accuracy and spam limited temporal increment for cooldown reduction.
-You're gonna need a lot of boolets and a lot of repair kits. Thankfully, you have enough strength to carry 1000 rounds of 7.62/8.6mm ammunition and still loot like a madman.
-High melee skill and decent strength means you'll be able to use every melee weapon class (with your base stats) short of tungsten sledges in the early game, so this can be handy if SMGs/guns are falling short. You won't have any melee-oriented feats, but this shouldn't be too much trouble early on when the game doesn't expect a focused build and your SMG will be least effective.
-You will not be critting much, so tungsten carbide ammunition will be your best friend against tough guys until you can get expose weakness, at which point you should still probably use tungsten carbide ammunition anyway - life will be much easier, though. Crits aren't that great for SMGs anyway, so I don't consider this to be much of a big deal.
-Wait, you actually will be critting a lot - but mostly with grenades and throwing knives thanks to three-pointer and fatal throw. Bathe the battlefield in sharp, flying bits of metal as you vanquish every pipeworker that gets in your way.
-You can actually be quite tanky for a zoner with only 3 constitution and psi empathy, and this is the main reason for having 8 strength: Super Steel armour. Be a good little saver, make sure you get high quality super steel plates and combining super steel boots, helmet and singly-reinforced armour (2 super steel plates for the chest armour, to make that clear) will net you a damage resistance near the cap, easily if you use high density foam for the helmet and boots. For even more ridiculousness, nab a high-quality regenerative vest and you will be healed nearly to full every time you dip just below 70% health.
-Low armour penalty from combination of nimble and armour sloping will mean that your movement penalty will actually be quite low. Your secret weapon for perfecting the survivability of this build is a 150+ quality boot spring. With it, you can ensure that despite being fully clad in glorious metal splendour, you regenerate a full 40 MP from hit and run every time you decorate the rails with an enemy. How often will you be doing that per turn? Well...
-At 16 dex, with a rapid 7.62mm jaguar, each burst will cost you 12AP. Taking into consideration 20 AP from adrenaline, 15/20 AP from contraction, ~ 10-15 AP from fatal throw, 9 AP from commando, up to two AP regenerations from my rapid reloaders and a free burst with my offhand muzzled 8.6mm steel cat from commando, and the lead takes a long time to stop flying all over the place - especially considering possible investment into full auto.
At 18 Dex, A 7.62mm impala becomes a straight upgrade to the jaguar as far as I'm aware, due to them having the same stats barring critical chance. The difference in per-turn AP expenditure between 16 and 18 Dex is overall quite unremarkable and perhaps optional, though I like pumping my damage potential as high as possible.
Of course, this is at the high end of stat investment and specialisation, but even with 14 ap bursts that you'll be able to perform from level 8 onwards with a rapid 7.62mm jaguar you'll be shooting a lot per turn.
-Keeping a light melee weapon on you to apply expose weakness won't eat into your AP badly thanks to your high Dex and will hit reliably thanks to your maxed melee skill. I like the power fist for this, thanks to the strength bonus and the ability to incapacitate enemies for a good long while, potentially enabling a retreat if you leave them blocking a choke point. Knife thrower's glove can work too, as this will keep AP costs for fatal throws down.
-This build is able to wipe the floor with the Sormibaeren at level 24 as long as you have antidotes and prioritise psykers as you should. Anything you add by way of feats beyond this point is icing on top of icing on top of a cake. Premeditation and Future Orientation make it even more ridiculous, but are in no way mandatory. You may not want to invest so heartily into throwing either, it just seems like a no-brainer to me as a Dex and throwing knife enjoyer.
In summation, you can throw extremely deadly grenades and knives with as unerring accuracy as you can hope for, tank a decent bit with your fancy shiny armour, run around like a bat out of hell with Hit and Run and dominate many zoners per turn with your extremely AP-efficient bursts. I had a great deal of fun with this build and it turned out to be pretty overpowered with its combination of mild tankiness, high mobility, and high firepower, which is my main reason for wanting to share it.
