The MP7 is described as:
This SMG’s smaller rounds help reduce its recoil.
You can find this gun in central Barvechos province, in a Santa Blanca outpost just west of the city. The weapons case is at the top of a sniper tower.
If you approach this outpost via the road that goes through the middle, you can stop and take out the sniper in the tower first, then with all the other enemies tagged, continue to take out the rest.
With its integrated foregrip, the MP7 achieves a maxed out handling rating, best in class noise reduction and also has a high rate of fire.
I really wanted to use and like this SMG – it having been a great gun in other games – however the recoil is quite unpredictable on it in Wildlands. Sometimes it’ll pull up and to the right, sometimes it bounces left and right, or just laterally.
I’ve tried swapping out some accessories to improve accuracy but nothing can dampen that recoil pattern for me unfortunately, so I just never use this gun.
If you want to persist with this gun, you’ll want to increase the magazine ammo from the standard 20 round magazine to 30 rounds (found in Mojocoyo) with its special HK4.6 ammo.
Maybe pick this gun up and give it a go yourself and see what you think.