Warning: Long defence of Chem ahead!
I forgot why I took the SMGs with chem while I was playing and writing the report.
The idea was to have a plentiful supply of armor damaging capabilities, not damage. SMGs are pretty inaccurate, so you need to be up close, where you might as well use melee, so the point is not really damage (although I really like your idea of a "melee failsafe"! I will be using that!). In fact, in the mansion, only once did I use the SMG, and it was more out of spite (with a gal that just got injured, to kill her Guild Security attacker, which she did manage to do on front armor) than it was out of reason.
When I prepared for the mansion, I expected at the very least some personal armor type enemies. Marsec or Osiron, depending on the faction I would get (I went in blind as far as faction and deployment were concerned). I somewhat expected enemies similar to church exalts:
The rich and mighty may well have fancy "hunting" gear that could also be used to defend their home.. I wanted to be able to tackle those and hopefully reduce their armor enough to be able to stun them and bring them to the Harpies' nest too. I also expected to meet foes that should prove too much for the unprepared, forcing them to perform the mission as presented: Grab loot and run away from too big a challenge, instead of what I (and I think most others) did: Kill and clean. I was intending to try and do the epic fight against such foe to clean the house.
So the idea was to have acid flasks in good supply and SMG-Chem as a side for melee gals and bad throwers. Each burst could do ~8 armor damage if all hit (from very close), since it is 10% of 0-48 damage, so 0-4 -> 2 on average, 4 times. An autoshot is also is really fast so you can have a few gals run in, unload and run out. Since even power armor has "only" 65 rear armor, a few full autoshots to the back can make even that manageable with pipes (~60 damage, so if you bring down the armor to ~40 in a few autoshots, you can then hurt it relatively reliably).
The different SMGs ammos get:
- Chem: 0-48 damage, 0-4 armor damage, supposedly a 10/40/30% bonus damage to Combat/Carapace/Power armors
- Incendiary: 0-40 damage, only 50% armor, supposedly 0/25/85% damage reduction to Combat/Carapace/Power armors
So a chem round should do up to 67 damage on carapace, so you can do up to 17 damage on front armor, up to 37 in the back. Power armor is rear 65 and you do up to 62 damage, so after ~1 burst, you can potentially do damage, and every hit reduces armor, so keep applying it and it will eventually work. That's why I like Chem. And of course, you can eventually just go all in and smash them in the back with a melee weapon. I found some spiked maces and billhooks during the mission, which would totally have allowed me to take on power armor, especially with a sprinkling of chem first. Even pipes will work after a (un)healthy dose of chem with their ~60 damage with 80 strength gals.
By opposition, an incendiary round does 0-30 damage on carapace, which goes against 15-25 armor depending on facing because of the 50%. That means you need better than average damage to penetrate side armor and will do up to 15 damage in the back, down to 5 in the front. Of course, against power armor you can fire until you're out of bullets and they will still be standing. So it works better against low armors, but that's not the problem I was trying to solve.
Obviously I was preparing for a challenge much above what the mansion actually presents in term of combat. The challenge is more one of perseverance to clean up. And since I faced traders, they were actually chem resistant.. But the magnums worked really well and I will take them again. The SMGs.. I'll probably keep them in mansions, not because they work any better than other stuff, but because they will eventually work against anything.
I don't really get how to do a "snatch and grab" though.. there isn't an obvious vault or something, and scouring the whole mansion for valuables will require you to kill most of the enemies, so you might as well finish off the few stragglers..? That seems to go with pretty much everybody cleaning up the place.