The Shift Short Angled Grip is described in the game as:

A foregrip that assists in muzzle control, but adds some weight.

It’s found in central Barvechos, in the mine quarry. The accessory case is on a shelf in one of the warehouses.

So… if you come to the quarry specially to get this accessory, there are no hostiles, only some civilian miners around. However, you may come here as part of the first story mission in Barvechos “El Pulpo’s Right-Hand Man”, where you have to come and get Wagner from this same room. If so, you’ll be under time pressure for the mission and there will also be some cartel around, so don’t forget to grab this while you’re there. It’s right next to Wagner in the room.

Finally on getting here, the roads down to the quarry are windy and annoying. I highly recommend using a helicopter!

So, like the AFG (also in Barvechos), the Short Shift Angled Grip – which is a mouthful of a name by the way – does the opposite to the other underbarrel foregrip accessories, by improving accuracy while reducing handling.

If – like me – that’s your goal, then this is definitely what you want on your underbarrel for certain guns. I use it on my sniper rifle for the added accuracy!

Alternatively, for assault rifles the only other underbarrel option is a grenade launcher. If that’s your bag, definitely take a look at the M203.