M320 Grenade Launcher: Under-slung vs. Standalone

Solution 1:

Not underslung:

• 1 second switch time
• 3 second reload time

Underslung

• 1 second switch time
• 3 second reload time
• You have to give up bipod or foregrip

Everyone has to decide for themselves. But personally I think using it underslung is a joke.

Solution 2:

The M320 is a stand-alone grenade launcher in the "gadget 1" slot. Medics, for instance, must give up their med-kit in order to use an M320. I've seen a lot of questions about this related to the underslung rail. The underslung rail is supposed to reduce the time it takes you to switch to the M320. Even though the underslung rail supposedly mounts the grenade launch under the barrel of an assault rifle, it still takes up your gadget slot- so you must still give up the med-kit to use the M320.

Solution 3:

There is a video on youtube by user Darius822 that measures the switching times to and from the M320 grenade launcher and the M416 assault rifle:

According to the video's description, he used macros to trigger the weapon change to make sure the timings weren't affected by human errors.

Results

Underbarrel:

Switching to: 18 frames = 0.6sec
Switching from: 16 frames = 0.53sec

Separate:

Switching to: 17 frames = 0.57sec
Switching from: 24 frames = 0.8sec

Conclusion

So it seems there is a small performance gain by having it mounted underslung when switching from it back to the assault rifle (50% faster). That could mean surviving a sudden encounter with an enemy...