You can still use the WSTE-M5(s) when you have one shell left, even though it takes two shells to fire.
If you are under four shells, if you hold down both fire buttons quick enough, you can fire both WSTE-M5s at the same time as if you had four shells.
Bobbing is jittery if you're dual-wielding the WSTE-M5s and you're holding the primary fire button when you're completely out of shells (or when you're underwater).
You can still use the WSTE-M5(s) when you have one shell left, even though it takes two shells to fire.
If you are under four shells, if you hold down both fire buttons quick enough, you can fire both WSTE-M5s at the same time as if you had four shells.
Bobbing is jittery if you're dual-wielding the WSTE-M5s and you're holding the primary fire button when you're completely out of shells (or when you're underwater).