Either the game's got something fucky, or I'm really bad at it. The threats don't seem to be scaling (But at least savescumming is an option on reload anytime mode). I'm running with SKSes, which are respectable enough against humans, even those with armour thanks to AP rounds.
So the game decides that I need mechanoids instead. Mechanoids need heavy weapons to deal with effectively because they tend to have good armour and lots of health. On top of that, they have turrets that are straight up evil. They spew a metric fuckload of high damage rounds at extreme ranges, and in spite of having the accuracy of a drunkard, the sheer volume of shots means that you're going to lose at least on person per volley. Armour doesn't help, their shots go straight through even cataphract armour, and have an annoying propensity for hitting your guys in the head and decapitating them. Ignoring when the game decides to send inferno cannons at you, those are even worse because they not only have insane range, their attacks produce *enormous* explosions at a decent enough accuracy to hit nearly every time and when your guys are set in fire, they run everywhere. Often out of cover straight into the middle of a heavy charge turret's volley.
Anyway, had a mechanoid cluster spawn next to my base. It was producing toxins. Headed over there, the cluster was asleep and the toxin spewer was outside the range of the motion sensor, so I destroyed it. Then I learned that you can't reform the caravan until every enemy is dead. I managed to kill every mechanoid with minimal injury.
Apparently "enemy" includes "Automated turret".
Four mini sluggers and three heavy charge turrets with minimal cover. Savescum back to before that event fired because I can't kill those without mortars or a high casualty rate (Or, significantly more likely, a squad wipe)
Rimworld