So, this may or may not be the right place for this? It's a question regarding people's tactics and builds...and maybe some new players can scroll through and get some ideas. Maybe I can.
Here is what I do/use for random PvP
When it comes to just general "free roam waiting for someone to sneak attack me", it's
Never Without One, Sharpshooter, Iron Lung. Paint it Black Deadeye.
Carcano, Repeater (any) and Pistols (Mauser or Semi)
Note: Typically, I won't carry a shotgun unless I wanna spam incins'...and you'll probably agree that's what 99% of people use them for. But it could be worth it in Saint Denis.
This is my go-to all purpose setup. I pick IL over FMO because most of the time, taking repeated body shots isn't part of what's going on in random PvP...I'm dying from headshots up close, or getting 2-3 tapped by snipers. The two cards are functionally the same in that area, and I even get a little bonus stamina regen from IL. Helps with diving.
FMO is better for PvE, and fighting multiple newer players who do nothing but body shot me. Winning Streak is good for countering FMO, and not much else. Again stacking damage isn't typically what's going on...in random PvP fights, I either headshot them or 2-3 tap them with a sniper.
Also, pistols are effective alot further out than people seem to think. I catch alot of people off guard at medium-ish range while they're trying to fire they're Repeater at me, I just go Brrrrrr.
Note: tonics and gold cores can drastically alter how a sniper battle plays out. If you're using this build and someone takes 4+ hits from a CLEAN carcano with Express rounds...yeah, they're chugging tonics like a mofo.
Also, everything I just said is assuming two people are using PiB.
Which is what I typically run into...but that's me. And this is my general purpose build, not a specific counter to slippery or SnS. I'd elaborate but this is already too long.
So let me know what you think, drop your favorite build for general purpose, and let me know why you like it. I'm curious to get new perspectives.