So I've been a forums lurker for the past few... years, and after the last build, I noticed that one of the new "innovations" was the ability to shoot through allies. Anyways, one of my old favorite "gameplay modes", was to put a bunch of actors around a map, and play sandbox with them, at my own pace. Obviously, not being able to shoot my own players pretty much doesn't let me do this.

(Basically, I would set up a little base full of actors and "infiltrate" my own base with superactors or such and make up little stories in my head, like a literal sandbox.)

So I've heard that there's a new code to activate this in actors, and I've recently forgotten it. But regardless of what it is, is it possible to "bulk-deactivate" this feature from the game? It would be prrreettyyy ace if I could.

(Could someone at the very least tell me the code so that I could manually do it?)

What you're looking for is the IgnoresTeamHits attribute of MOs, you'd have to set that to False (0).
This piece of code should work, though I haven't tested it:

What it does is that when it is attached to an MO it enables friendly fire for every MO on the scene.