Bullet impacting mortar shell/grenade?!

[Caradhras]

In my campaign some 'bad guys' were in cover (behind wall) and my player (sniper with Barrett) dropped one that made a run for it. He asked me if he could see any grenades on the body through his sights as he had fallen not far from the corner. I knew the NPCs had a 60mm mortar and rolled a chance this guy was carrying shells..he was. The player makes his roll to spot one, aimed shot @ 1/2 normal to hit it...and boom.

Now, I dont know how unrealistic this was. But my sniper player has a taste for it now so I would like to know before I compund my error - if any - for allowing it.

[Fusilier]

Bullets can detonate grenades. I have a picture of a poor fella in a landing craft at Normandy. His in the midst of blowing up after a MG round struck his grenade.

[Legbreaker]

But it'd have to be a spectacularly good or exceptionally lucky shot!

To set a grenade off, or any charge for that matter, the only possible way I can think of would be to hit the detonator which is usually (depending on the actual munition) about half the size of a ciggarette. Add in that in muntions (demolition charges are different on the whole) the detonator is concealed within the round, and factors such as range, movement, wind, and a billion other things, and there's probably less than a snowflakes chance in hell of pulling it off.

So, yes while it's possible, it's absurbedly improbable.

[Eddie]

You're wrong, Legbreaker.

That is exactly why the Barrett is designated an Anti-Materiel Rifle, not an Anti-Personnel Rifle.

EOD uses the Barrett to explode UXO (UneXploded Ordnance) all of the time, Caradhras. While Legbreaker was right about difficulties to the shot, those difficulties are no more extraordinary than any other targets a sniper aims at.

Is it 100% effective? Not always, no. So I'd put in a probability check of maybe 60%-65%. But there is nothing wrong with what your player wants to do.

[pmulcahy11b]

My simple answer is: Can it happen? Yes. Is it likely to happen in normal combat circumstances? No.

It falls under the category of "lucky shot."

[Targan]

Depends on the type of grenade but I'd have to agree with what Eddie and Paul said.

[Legbreaker]

Well a Barret is a different kettle of fish and there's a hell of a lot more energy involved than a "standard" 7.62 or 5.56 round, so perhaps it might actually do something.

On the other hand, I'm just not convinced that a solid projectile of any size is likely to impart enough energy into a secondary charge (the bulk of most explosives). If it were an explosive round of some type, then I'd up the chance, but it's always going to be a very, very difficult shot, made all the harder by the explosives contained with in the round being hidden from view and the fact that although it's seen time and time again in the movies, it's a REALLY bad idea to carry grenades hanging from their pins or the "spoon". Instead, they (at least in my experience in the Australian Infantry) should be carried within web pouches.

Add to that the Barret, and all antimaterial rifles for that matter, are quite bulky, and not exactly suited to shoot at a target about the size of a mans palm, that's presumably moving around A LOT if they're in combat.

So, once again it's possible, but don't count on seeing it happen even twice in a lifetime.

[General Pain]

But it'd have to be a spectacularly good or exceptionally lucky shot!

To set a grenade off, or any charge for that matter, the only possible way I can think of would be to hit the detonator which is usually (depending on the actual munition) about half the size of a ciggarette. Add in that in muntions (demolition charges are different on the whole) the detonator is concealed within the round, and factors such as range, movement, wind, and a billion other things, and there's probably less than a snowflakes chance in hell of pulling it off.

So, yes while it's possible, it's absurbedly improbable.

Don't forget in an infinte universe everything is possible.

an on a side note:

Murphy's law is still pretty constant around the world.

on the other side, I can see how it would be difficult, but this is a game and fun is part of it I'd allow it....That means that NPC snipers can do the same to characters he he... Just imagine a pro sniper with a .22 LR sniper rifle plukking of PCs with Frags attached to their Alice.

Don't say NO - Just determine difficulty.

****

Jim Carry said in one of his movies:

Jim: would u go out with me
woman: not in a million years
Jim: So you're telling me there is a chance?

[Legbreaker]

Just imagine a pro sniper with a .22 LR sniper rifle plukking of PCs with Frags attached to their Alice.
Can't forget that a heavy shirt is likely to stop those .22 slugs in their tracks too, so getting through the casing of a grenade.....

[pmulcahy11b]

Don't say NO - Just determine difficulty.

I like that philosophy, and used it when I was a GM. However, I've been known, when a player really wanted to do something close to impossible, to hand them a d20 and tell them, "Roll a 1 -- four times in a row."

[jester]

Remember they used marksmen to take out mines on minesweepers and even EOD has marksmen to shoot explosive devices.

[Legbreaker]

Remember they used marksmen to take out mines on minesweepers and even EOD has marksmen to shoot explosive devices.
Good point. Can anyone elaborate on just how it's done though? Is there a specific location on a WWII sea mine to hit? They were certainly a much less sophisticated device than the majority of today's munitions.

I beleive EOD still has to determine the actual location of the charge they need to strike before the shot, which is usually made easier due to the immobility of the device and just about every advantage possible given to the marksman (device schematics, nice comforatble firing position, no requirement to take the shot instantly, etc.)

What about the use of special ammunition? Are there any rounds specifically designed for EOD?

I've also heard of robots armed with "water knives" similar to those used in precision engineering, shooting and destroying components of bombs, but once again, they're set up very carefully to hit the perfect component in the bomb to defuse it.

[Eddie]

The kinetic energy delivered by a .50 caliber round to an unexploded device, combined with the heat from friction is enough to detonate most rounds. The .50 will punch through the shells of most artillery rounds. Basically, wherever you hit, as long as it is in the center of mass, you're very likely to detonate the round.

No rounds are specifically designed for EOD. M8 API rounds work very well for EOD applications though.

Most EOD units do not have robots equipped with that. They use water impulse charges to achieve the same effect with a more conventional robot.

[jester]

Seamines and WWII;

I beleive they were required to hit the prongs on the side, at least that was what was said on a program on the history channel the otherday when they had a program on minesweepers and mines.



As for EOD, I was looking into it kinda half assed am still. The MOS info goes on about sending some of their personl to sniper school. It could be a come on for recruitment or for filling other roles.

Water charges: They again had a program on that on some channel the other day as well. Them dammned Canadians came up with it. Which blows the entire device to pieces using the force of the water that is non compressable. They showed alot of video of it, blowing 105 rounds all over as well as the contents of the tunk and the rest of the bombs. It was cool! <Basicaly a water claymore, using the water as a shaped charge.>

Robots, many of them at least in civi hands have shotguns. They used one to deliver a message to Randy Weave of Ruby Ridge Fame, he refused because the robot had the shotgun on it and per his Senate Testimony he was in fear for his life.

I also saw durring an event near my office down town when the police cordoned off a street and sent in their robot, after fouling up the manipulation of their robot, knocking the case over, dropping it, almost knocking it down the storm drain, pulling the plug on it because the power cord was not longer enough they shot the package with the mounted shotgun which blew the package to pieces.



I would suggest:

If one were to shoot specific components of a device you could damage it and prevent it from detonating. Especialy devices with electical components.

I further suggest that rounds that are not fused will not explode with just a rifle shot. Comp B and C-4 are probably some of the more stable explosives out there and C-4 well it is used and abused by troops in the field with out any ill effects.

I think if you can damage the mechanism without detonating the blasting cap/detonator then you can render the explosive safe. However most blasting caps or detoantors are a bit sensitive. So, a round hitting the thing is lible to set it off which would in turn set off the explosive.

A problem with mortar rounds and some other rounds. They have an internal safety. They will need to be fired and do several rotations <also with rounds fired from a grenade launcher> to have them arm. So, that gives a chance of the device not exploding if hit.

[Legbreaker]

That's almost exactly my own thoughts there Jester. The aim with most EOD missions is not to cause the charge to go off, but rather damage the mechanism and components in such as way that it can't go off. At this point the device can be removed to a location where it can be properly disposed of (usually in a safe area where it can be destroyed with a controlled charge).

As you say, modern explosives such as Comp B, etc take a hell of a lot of energy to set off which is why they require a detonator and primary, or "booster" charge. Remember these things "burn" at around 4,000 metres per seond and up, up, up! A .50 BMG is only moving at approximately 850 mps and despite it possessing a hell of a lot of kinetic energy, I just don't think there's enough transfered over into a secondary charge to se it off.

This would be why the target for the sea mines has to be the prongs, or with all other munitions, the very unstable and extremely volatile detonator (the warmth of a persons hand can set them off which is why we were trained to hold them by the end like a ciggarette).

With regard to mortar rounds and other larger munitions, I believe they aren't actually fused until the last few moments before firing (at least that's how it worked on the few occasions I was arround the mortar plattoon). This, in addition to the safety mechanisms mentioned by Jester, renders the rounds very, very safe from small arms and shrapnel hits (although a nice large HE round would probably do the job).

And so, I repeat, while it is possible to set off a grenade or other explosive with a gunshot, in practise it's virtually impossible, especially in a combat situation where the shooter is extremely unlikely to be able to aim properly.

[Eddie]

Okay, I'm going to try and not come across as a dickhead...but I don't understand why the fact of EOD using the Barrett and the practice of shooting rounds is still under debate? I am telling you, from a real-world, operational, first hand viewpoint, that it can and does happen.

As for EOD, I was looking into it kinda half assed am still. The MOS info goes on about sending some of their personl to sniper school. It could be a come on for recruitment or for filling other roles.


I had EOD guys in my Sniper School class in '97. I've seen them use the Barrett downrange, as well.

Water charges: They again had a program on that on some channel the other day as well. Them dammned Canadians came up with it. Which blows the entire device to pieces using the force of the water that is non compressable. They showed alot of video of it, blowing 105 rounds all over as well as the contents of the tunk and the rest of the bombs. It was cool! <Basicaly a water claymore, using the water as a shaped charge.>

They're also valuable for document recovery from safes and breaching large metal doors.

Robots, many of them at least in civi hands have shotguns. They used one to deliver a message to Randy Weave of Ruby Ridge Fame, he refused because the robot had the shotgun on it and per his Senate Testimony he was in fear for his life.


Most military EOD teams don't have these. Most likely they're at the EOD company-level and are brought out only when needed as EOD never seems to give a rat's ass about the guys out there on the cordon.

My platoon had to wait four hours one night when we found a cache of 306 assorted artillery rounds for EOD to make three trips with a tiny trailer instead of bringing out their one big trailer. Go figure.

If one were to shoot specific components of a device you could damage it and prevent it from detonating. Especialy devices with electical components.

That's a technique. Generally you wouldn't want to do that with a device like that. At least, I never saw EOD do it. I can email my buddy that became an EOD platoon leader if you really want to know.

I further suggest that rounds that are not fused will not explode with just a rifle shot. Comp B and C-4 are probably some of the more stable explosives out there and C-4 well it is used and abused by troops in the field with out any ill effects.

But rounds are not loaded with Comp B and C-4. TNT, White Phosphorus, Smoke, Concrete, all different kinds of things. Propellant. Primers. Fuzes. There are a lot of parts to a round that will detonate from a bullet impacting.

I think if you can damage the mechanism without detonating the blasting cap/detonator then you can render the explosive safe. However most blasting caps or detoantors are a bit sensitive. So, a round hitting the thing is lible to set it off which would in turn set off the explosive.

This is the primary time that EOD uses the technique of shooting rounds. Rounds that have been armed and not detonated on impact, that is.

[Eddie]

That's almost exactly my own thoughts there Jester. The aim with most EOD missions is not to cause the charge to go off, but rather damage the mechanism and components in such as way that it can't go off. At this point the device can be removed to a location where it can be properly disposed of (usually in a safe area where it can be destroyed with a controlled charge).

Are we talking about "charges" or are we talking about "rounds". The two are different things.

As you say, modern explosives such as Comp B, etc take a hell of a lot of energy to set off which is why they require a detonator and primary, or "booster" charge. Remember these things "burn" at around 4,000 metres per seond and up, up, up! A .50 BMG is only moving at approximately 850 mps and despite it possessing a hell of a lot of kinetic energy, I just don't think there's enough transfered over into a secondary charge to se it off.

A bullet isn't enough to set off Comp B or C-4 on it's own. It requires heat and pressure. Burn the C-4 and shoot it. Burn the C-4 and stomp on it. But just shooting, or stomping, or burning will do nothing.

This would be why the target for the sea mines has to be the prongs, or with all other munitions, the very unstable and extremely volatile detonator (the warmth of a persons hand can set them off which is why we were trained to hold them by the end like a ciggarette).

Are you talking about blasting caps? The silver "detonators" used with M112 C-4 blocks? You're taught to hold them that way because they're sensitive to the static charge build-up in your body. If you're talking about another kind of detonator, then you may be correct. The silver blasting caps are all I've used since 1996.

With regard to mortar rounds and other larger munitions, I believe they aren't actually fused until the last few moments before firing (at least that's how it worked on the few occasions I was arround the mortar plattoon). This, in addition to the safety mechanisms mentioned by Jester, renders the rounds very, very safe from small arms and shrapnel hits (although a nice large HE round would probably do the job).

When I was Infantry Mortar Leader's Course, our rounds came fused and with the little cheesecake propellant charges on the bottom. They have a safety that has to be removed to make them fireable though.

What happens is in the ASP/DHA, the rounds are separate from the fuses for long-term storage, but when a unit requisitions them, their ammo detail breaks the stuff open, fuses them, preps them for mission, and then sends them to the line.

And so, I repeat, while it is possible to set off a grenade or other explosive with a gunshot, in practise it's virtually impossible, especially in a combat situation where the shooter is extremely unlikely to be able to aim properly.

That's a pretty broad statement. I want to specifically address the last sentence, extremely unlikely to be able to aim properly? Define aiming properly for me, please? What necessarily prevents one from aiming properly in combat?

[Legbreaker]

Are we talking about "charges" or are we talking about "rounds". The two are different things.
Mixing and matching a bit I think.Are you talking about blasting caps? The silver "detonators" used with M112 C-4 blocks?
It's been something like 15 years since I laid my hands on them myself, so you're probably right. We weren't using C4 though, so...

That's a pretty broad statement. I want to specifically address the last sentence, extremely unlikely to be able to aim properly? Define aiming properly for me, please? What necessarily prevents one from aiming properly in combat?
Movement for one. Chances are the target isn't going to be standing still while you line up for your amazingly accurate shot at their grenade pouch. There's probably a good chance you yourself might be being shot at too, which really tends to reduce the ability for one to zen out and follow everything you might do on the range.

Of course there are always exceptions to the rule, but it'd still be a very, very difficult shot to pull off!


I believe the prefered method of "disarming" a charge is to simply blow it in place by putting another controlled charge next to it - this avoids the risk of it going off while working to disarm it or move it to a more "convieniant" location. Of course this isn't exactly an option in a built up area or where you want to minimise damage to the surroundings.

There are probably as many different techniques as there are people with opinions, and device configurations - shooting at it, blowing in place, drowning it, etc, etc.
However, EOD is primarily if not solely focused on minimising damage which is most often achievable by removing the ability of the charge to detonate.

The purpose of this thread is to ask the question, can a round be detonated by a gunshot, which I think we can all agree is possible, just highly improbable?

Something else that might need to be kept in mind, particularly from a roleplaying point of view, is the actual effect of the round detonating. In WWII, my grandfather was an engineer with the RAAF working on Beaufort bombers. He was also a "Kings rifle" (later Queens), in other words, better than excellent marksman. In my younger years before his eyesight failed, I've seen him head shoot a running rabbit from the hip at a hundred paces.

As soldiers with some time on their hands tend to do, he and his aircrew "borrowed" a number of old 40mm Bofors AAA rounds which were past their use by date and had been dumped in a big hole ready for destruction by burning (tropics tend to deteriorate ammo quite fast). These were taken out bush and one set up on a rock about a hundred yards away with base facing them.

One .303 shot later and BOOM! The round was struck in the primer and the projectile launched forward. Simultaneously the casing was launched rearward - it passed within a hairs breath away from them and potentially could have killed either him or one of his crewmates.

Morale to the story - don't do anything STUPID!

[Targan]

The purpose of this thread is to ask the question, can a round be detonated by a gunshot, which I think we can all agree is possible, just highly improbable?
How about 'possible, just highly improbable but made more probable if an appropriate weapon is being used and/or the shooter has EOD skills and/or has other appropriate training'?

[General Pain]

Can't forget that a heavy shirt is likely to stop those .22 slugs in their tracks too, so getting through the casing of a grenade.....

granted ;)


how about a tad larger rounds like the 7.62N ?

[copeab]

Shooting guns? Blowing stuff up?

This sounds like a job for the Mythbusters ...

[Caradhras]

Dammit - wrote a long reply and it bugged argh.

not time to retype all but in summary....

My sniper player doesn’t try to hit the round/grenade of an active target – he is downing or scanning downed opponents that may be in the blast radius of others.

I roll a chance of visible round/grenade, he rolls a ‘recon’ to spot them, he then takes aim and I reduce his shot chance by half for a nominated target (like head shot) and then half it further due to small target. I will also add now a 33% chance the target wont explode effectively even if hit.

Thanks for all your input, helping to keep my game slightly more ‘realistic’ :P

[headquarters]

tried shooting sticks of dynamite once .

The US M1 carbine didnt set them of ,but my 30-06 K98 Mauser did .

It was really good fun -at app 100 yards with iron sights -I would say that its not totally impropable to do it .

The dynamite was of the kind you use in construction today .Dont remember the brand / type .

Interesting though ,that the M1 carbine - roughly equivalent of the .357 mag round didnt do it - whereas the 30-06 set it of every time.

I guess the make up of the explosive in the round will determine it .Many high explosives need more power than a rifle round to explode - indeed the antimaterial rounds dont always set mines etc of , but shatters the explosives so that they dont pose as big a threat for further UXO work .Most mortar ropunds etc will have some sort of pressure molded TNT type explosive .TNT is pretty robust , so I dont really know if a rifle round can set it of .

As for the game scenario this thread started with - sure -why not ? The detonator is a tube that extends down into the round, not just the little speck at the tip .Sure a good shot can set it off.But it comes down to the type of round etc -some are made with safety tolerances etc to safeguard crews against accidents .

[jester]

Keep this in mind,

the M1 Carbine round will loose alot of its energy rather quickly whereas the 30-06 will retains alot of its energy for a longer distance.

Also, keep in mind dynamite is made with more or less nitroglycerin. An uncle who is a geologist studied one summer working on a project in the mojave and he came upon an old mind <there are thousands out here> with a box of old dynamite. He had an enfield rifle with him and so he shot it from a few hundred meters. We are talking dynamite that was probably 60 or more years old. KAPOW!!! He told us he was not as far away as he should have been.

The same can be done with the ground near old explosives. Since the explosive will leak out of the case, through the create and into the ground. That would be a cool trick. Pour the liquid explosive into the ground of someones cold fireplace or campfire and then when they light their fire....POW!!!!

[Grimace]

If you're messing around with liquid nitroglycerin, you're asking to blow yourself up. Sweating dynamite is an explosion just looking for an excuse to happen. That's one of those things where coughing on it wrong can ruin your day big time.

As far as blasting caps, you've got two versions of potential danger with them. Electric detonation caps can be set off by static electricity on the body, or even radio frequencies in close proximity. Add in the nature of the cap itself, and a sharp blow to them will mess you up in a hurry. Fire detonation caps are more "stable" in the fact that they won't go off if you've got a radio on you or if you shuffle your feet around. However, you light a cigarette or create one too many sparks near the fuse end of the cap and you've got the same problem. As with the electric caps, don't go being rough with the caps. Just bend a cap and you'll pay for it with the equivalent explosive potential of a quarter stick of dynamite.

All told, I can certainly see a .50 cal being used to detonate explosive (mortar rounds, artillery rounds/powder charges, even grenades) devices as long as the target isn't moving. Put the difficulty as extremely difficult. Your common infantry guy isn't going to be doing it by any means. Snipers have the potential though. Yes, the chance of hitting something like that on a moving target is 1 in a million. Hitting it on a non-moving (aka dead) target is difficult, but a lot more possible for skilled sniper. Definitely don't allow it for something like a claymore, though....or other C4 charge. Those need detonators to set them off. Bullets are not the equivalent of a detonator in that regard.

[Targan]

Let me preface the following by saying that I am aware that the initial topic of this thread related to whether grenades can be set off by being shot, but it has since expanded to include EOD and whether other forms of explosive can be detonated with a bullet. I know much more about civilian/commercial explosives than about grenades so this post is my contribution to the EOD side of the discussion (in that an IED could just as easily contain military ammunition components as commercial or home made explosives).

I think actual dynamite (ie a waxed cardboard tube containing sawdust soaked in nitroglycerine) is pretty much a thing of the distant past in the western world these days. Packaged emulsion explosives such as Powergel are the modern equivalent to a stick of dynamite and are much, much safer, have a longer shelf life and their manufacturing processes are less hazardous and require relatively cheap and simple ingredients.

For civilian applications such as mining the most common explosive these days is ANFO (Ammonium Nitrate and Fuel Oil) which can be quickly and easily mixed on site using its basic components (essentially urea fertiliser and diesel). Packaged emulsion explosives also have Ammonium Nitrate as a major component in the form of microscopic droplets suspended in oil, wax or paraffin fuel and stabilised with emulsifying agents. ANFO is a low explosive and relatively difficult to detonate under normal temperatures and pressures. A half a stick of Powergel will do nicely as a primer charge to detonate a 10kg bag of ANFO. The Powergel itself will need to be set off with a detonator. Shooting a bag of ANFO or a stick of Powergel will not result in an explosion.

Detonators (electric or percussive) commonly contain PETN which is a very energetic, fast burning high explosive and and is much easier to set off. Avoid subjecting detonators of any kind to sharp blows, electric shocks, high temperatures, pressure shock waves and being shot.

A final note on fuses and other means of activating detonators and blasting caps. I only know the basics when it comes to the various fusing methods and mechanisms employed in military ordnance but for civilian applications the most common types of fuses used to set off detonators are Igniter Safety Fuse Electric (ISFE) for electric detonators and either Safety Fuse (like in the movies where you light one end and it burns at a hopefully accurately predetermined speed) or Shock Tube (hollow plastic tubing lined with a fast burning chemical compound which transmits a shock wave to one or more blasting caps). Another option is to use Det Cord as "fuse, instant" as it can be set off with a single detonator and will set off primer charges such as Powergel) connected along its length.

ISFE is obviously immune to being activated by being shot but a bullet could cut the wire rendering it useless. Shock tube will not be set off by bullet strikes though again it could be severed. Safety fuse could possibly be set off by a bullet but would more likely simply be severed. A bullet hit could well set off det cord at the point of impact and would cause the det cord to detonate both back to where the initiating blasting cap is (bad for anybody in close proximity) and also down the line to any attached primer charges.

[copeab]

I think this tread would be more interesting if the PC were acting as human point defense, shooting at incoming mortar shells or grenades ;)

[chico20854]

As far as blasting caps, you've got two versions of potential danger with them. Electric detonation caps can be set off by static electricity on the body, or even radio frequencies in close proximity. Add in the nature of the cap itself, and a sharp blow to them will mess you up in a hurry. Fire detonation caps are more "stable" in the fact that they won't go off if you've got a radio on you or if you shuffle your feet around. However, you light a cigarette or create one too many sparks near the fuse end of the cap and you've got the same problem. As with the electric caps, don't go being rough with the caps. Just bend a cap and you'll pay for it with the equivalent explosive potential of a quarter stick of dynamite.

Avoid subjecting detonators of any kind to sharp blows, electric shocks, high temperatures, pressure shock waves and being shot.

It's a wonder I managed to live through college without the dorm blowing up!

[Stackmouse]

As been said here before, shooting a artillery round or a mortal shell can detonate it, but the method is not that good because the chances aren't that good. Disposing explosive items by shooting them is a better method when dealing with scatterable mines, for example.

The explosive filler in most shells and rounds takes pretty much energy to go off, that is why most of them have a separate detonator made of more sensitive explosive. This detonator can be a part of the fuse, or it can be a part of the shell. The fuse mechanism causes the igniter to go off, which causes the detonator go off, which in turn makes the explosive filler to go off.

In most cases you need to go for the detonator/fuse to get the round to go off. And if it doesn't go off then you most likely have gotten rid of the fuse, so you are better off when you started.

I am EOD trained and occasionally do disposal work even if it isn't my "primary job". We don't use shooting as a disposal method, as it is not that effective (even if shooting a .50 rifle is always fun), but the method is the primary method for certain types of scatterable mines.