1. take weapon with under barrel launcher, load any type smoke grenade. have friendly player in front of you at short distance (e.g. 2-3m) fire at a location behind him. You will see the shell projectile go through the friendly's body and end up behind him on the ground.
2. take weapon with under barrel launcher, load any type smoke grenade. have friendly player in front of you at very close distance (we tried shooting the grenade in someone's face to see what would happen). You will see the shell floating in the air in front of the targetted player.