I usually keep pistols in my vest. When I go into combat using the pistol, a shot to my chest will ruin the pistol in my hand, thus disarming me.

This is also the case for guns that can fit in inventory like mp5k.

Please add separate inventory space to the hand, and add hitbox to the items so shooting only the item ruins it without hurting the player.

Shooting the gun will disarm the player, not the pants or the vest.