There are several other types of weapon, listed below, which are called grenades but which are either obsolete, useless or for special occasions only.
In essence, fragmentation grenades are for clearing trenches, bunkers and rooms without entering them. Phosphorous grenades are for clearing bunkers where a bend or a sump might protect the occupants from a frag grenade. Stun grenades are, as stated above, for stunning the enemy.
History: How did it develop to be the way it is?
Grenades started to be used in the 1400s and at this time were iron balls filled with gunpowder and detonated by burning fuses which stuck out – rather like the comedy bomb you might have seen on cartoons. The name comes from granado which is Spanish for the pomegranate which some think it resembles.
You can probably imagine that in a time of extremely slow rate-of-fire muskets and swords a thrown bomb was a pretty handy tool. By the 1800s the grenade had gone out of use but was revived in the Russo-Japanese War of 1904–5. Then there were a bunch of homemade efforts until the English inventor William Mills invented the excellent Mills Bomb in 1915, the pineapple grenade which has continued in use pretty much to this day. In World War I the British attached sticks and used a long fuse to make them easy to throw a long way. But the brave Germans threw them back so the fuse was reduced to the now standard 4.5 seconds and the stick binned. The Germans picked up the stick idea and developed it for use in World War II.
Since World War II the idea has arisen that by surrounding the charge with brittle wire marked into segments, rather than a cast-iron case, the shrapnel could be shared out more fairly with everyone getting a number of small pieces rather than one or two people getting big ones. I don’t see much difference in practice and I have used many different kinds of grenade. Indeed, I caught 13 pieces from a Russian fragmentation grenade and though it was the cast-iron type they were all tiny – perhaps a quarter of an inch long. They did sting a bit though.
Operation: How does it work?
A fragmentation grenade is not supposed to kill the enemy. It is unlikely to kill someone unless it explodes right on them or they are unlucky enough to catch a large piece. What fragmentation grenades are for, and what they do very effectively, is stun people long enough for you to get up close and despatch them with bullets or bayonets. Or, failing this, they make people seek a medic, a casevac and a ticket home. A fragmentation grenade is useful at night because it doesn’t give your position away and for clearing trenches, rooms or bunkers. Toss it in, wait for the bang, walk in and finish off the wounded.
The average fragmentation grenade is an ounce of explosive surrounded by something which will break up into shrapnel and spread itself around violently so everyone gets a piece. World War II grenades such as the British Mills 36 were cast-iron hollow pineapples weighing 27 ounces. Into this was packed an ounce of explosive with a hole up the centre to fit a stick fuse and detonator. Modern fragmentation grenades tend to have a similar charge surrounded by a thick layer of brittle wire. The theory is that a cast-iron body produced a few large lumps of shrapnel which might miss the target. With thousands of tiny pieces of wire everyone around is served equally. A sort of military democracy.
Concussion grenades are a larger charge but with no shrapnel. They are supposed to be more effective in a confined space but few soldiers are going to carry several types of grenade. So pretty useless and the sort of thing a bean counter would design.
A phosphorous grenade is unlawful when used against the enemy! They are outlawed by the Geneva Convention as they are ‘nasty’. But they are best for clearing bunkers where a person might somehow be shielded from the blast of a fragmentation grenade. If anyone stays in a bunker with a phosphorous grenade they will die, blinded and burnt, and if that doesn’t do it the poison will. A phosphorus grenade looks like a small aerosol can with the ubiquitous lever down the side. It is light and is used by taking out the pin and throwing – a long way. When it detonates it makes a gentle ‘pop’ and produces no shrapnel. What it does do is create an instant cloud of white phosphorous smoke filled with flying, burning lumps of phosphorous. The smoke burns lungs to a fatal degree and the lumps burn through flesh if they settle on it and set fire to wood. An immoral or amoral soldier might use a phosphorous grenade as an extremely effective and safe way of clearing a bunker. He would not have to go in but just shoot anything that blindly staggered out, which would in some ways be a kind of mercy killing!
Smoke grenades can be used to signal aircraft or to block the enemy’s view while you advance so they do have some use. Of course, you can also signal with a phosphorous grenade... Tanks actually carry Phosphorous shells for signalling if all the five radios break down and the radio tech cannot fix them.
Incendiary grenades are similar to phosphorous grenades but they employ a chemical reaction to burn at a high temperature – 2,200°– which is handy for setting fire to things but a phosphorous grenade will do that too.
Anti-tank grenades were developed in World War I and were suicidal for obvious reasons. They are now all obsolete. The early efforts were several fragmentation grenades in a bag. Eventually the Germans came up with a clever stick-on blast weapon which I will not explain here as a derivation could have insurgency applications. You will never tackle a tank with a bomb as the modern anti-tank weapons are so much better.
Stun grenades, or flash-bangs as they are sometimes called, make a very loud noise and a flash. Hence the words on the tin. The stun grenade is usually only issued to Special Forces and police when doing hostage rescue so you may never see one. I certainly hope you don’t get to see one as they are a waste of time. The idea is that you throw one into a room filled with both hostages and terrorists. The grenade makes such a loud bang and a dazzling flash that all the rooms occupants are disoriented long enough for the good guys to get in and shoot the bad guys. You can always tell the bad guys – they wear black hats. They do actually stun most people who are not expecting them but, in my opinion, it is often better to use a fragmentation grenade as a frag will definitely stun people and you can always patch the hostages up afterwards. They presumably don’t have a bus to catch.
Throwing a stun grenade. Although issued to SF soldiers for hostage rescue I generally consider them a waste of time. (Barry Lloyd © UK Crown Copyright, 2010, MOD)
If you ever have to resolve a hostage situation on the fly, so to speak, toss in a standard frag grenade especially as you are unlikely to have any stun grenades.
Tear gas grenades are used against rioters and have the effect of making the eyes run and throat burn a little. They are only marginally effective as it would take concentrated gas in a closed room to truly incapacitate anyone. Puke gas (exactly what the name implies) is far better as even a whiff of this will have even the most hardened rioter bend double throwing his guts up rather than throwing rocks at you.
Sting grenades use rubber balls instead of shrapnel to cause pain to rioters and are generally a waste of time.
A Molotov Cocktail is usually what people call a bottle filled with petrol and a burning rag in the top. The real McCoy is a little cleverer but I had better not explain how to make one here as this information could easily be used by the wrong kind of people. It does not need lighting and bursts into flames on impact. Its obvious targets are humans, vehicles and buildings.