There are many myths surrounding grenades in movies. But we’re going to focus on how the movies show that removing a hairpin from a grenade with your teeth before throwing it is something that people can do. In real life, this is not how these weapons work.
As grenades are full of shrapnel that can neutralize targets and even kill them if they are close enough, their pins are specifically designed not to come off easily. It also depends on the grenade.
Some types of pomegranate pins are widespread, others require some twisting and turning. In almost all cases, pulling the pins with your teeth will prevent you from having them.
The tip of the pin is usually wide apart. This ensures that the pin will not be torn off accidentally and will not simply fall out. Soldiers work in harsh environments and you will not want a branch to pull the grenade ring around the belt. This deployed pin means that a hand grenade requires a little bit of force – sometimes soldiers unfold the tip of the pin to make it easier to pull the ring.
Of course, hand grenades are designed to be used by normal soldiers – it can not be too difficult. It is estimated that a standard American M67 grenade required a force of 3 to 5 kg for its pin to be removed. Not too hard, but not suitable for teeth anyway. People also say that Russian grenades are harder to use in this regard. This means that you will need strong teeth to remove the pin from the grenade.