What is underbarrel shotgun?

[BabyPanda]

I want to unlock ak 5c, the 10 kills or assist under-barrel shotgun never moves. Actually which gun and attachment I have to use to let it count?

[[ACPL] Jon]

I'm guessing M26 MASS attachment. Available in HK416 as far as I remember.

I think basic M5 aka the starting gun has one, too.

[MrOnyx]

I used the Underbarrel shotgun the AK24 has; it doesn’t matter what weapon you use. A recommendation I can give is to use the underbarrel shotgun like a primary weapon.

[BabyPanda]

引用自 MrOnyx：

I used the Underbarrel shotgun the AK24 has; it doesn’t matter what weapon you use. A recommendation I can give is to use the underbarrel shotgun like a primary weapon.

the masterkey?

[BabyPanda]

引用自 MrOnyx：

I used the Underbarrel shotgun the AK24 has; it doesn’t matter what weapon you use. A recommendation I can give is to use the underbarrel shotgun like a primary weapon.

I will just do co/op, easy to get kills

[BabyPanda]

引用自 ACPL Jon：

I'm guessing M26 MASS attachment. Available in HK416 as far as I remember.

I think basic M5 aka the starting gun has one, too.

I saw ak24 and m5 also has something called masterkey

[[ACPL] Jon]

Yes, "Masterkey" is a popular nickname for an underbarrel shotgun.