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.