If you are playing with a Gamepad, or in my case streaming to the steam deck, it appears that automatic fire guns, when using ADS will after the first three or so bullets begin aimbotting towards the chest of the the nearest living enemy within a certain degree of where you are currently aiming.
Aside from these first few shots, the rest will unerringly land in this particular spot on their chest. If firing into the poxer hoard it will mow down enemies on the left and right both, and sweeping upkeeps the effect. If you aim exactly between the gunner and the mauler, it will actually alternate and hit both
As an example if you aim at the maulers feet while using this feature, all shots hit the chest unerringly. You can even aim to the right side of his body and still hit him with the automatic volley.
This does not work with any braced guns including heavy stubber, I have tested so far. Nor with the one recon lasgun I had access to, likely because the lasers would reveal the aimbot function too easily. But I of course do not have all weapons.
Current requirement seems to be any of the infantry autoguns, while using aim down sight and using full auto.
This requires further testing.