fastest way to unlock RPG7?

[Garrus]

I didn't know i had to pick it up to unlock it. I've encountered em many times but never bothered to pick one up. I'm in john seed's territory. Wheres the easiest to find.

[Llanicus]

like the previous games, picking up a weapon of a dead enemy will unlock the base version in the store, and just like the previous games look for the cultists with the target symbol over their head as they will have either a sniper rifle or rpg.

you can also find resistence members with them as well