Prototype weapons

[Midice]

Other than the ones you get in pursuits, how do you go about acquiring the others? Ark falls? Co-op missions?

[Zenislav]

One drooped from me randomly after mob kill. So far looks like it is just very small chance to get it from anywhere where you could get random weapon. Like mob drops, arkfall and coop chests, random rewards from events.
Need confirmation on some drops but I can say for sure very small chance as random drop from mob kill as that is how I got mine.

[outbackjim21]

Read the description of the prototype weapon you’re looking for and it will tell you what mob you have to farm.