Weight of a Boom gun round

[yoshidwyn]

Hello,

I am trying to find the weight of a single round of ammo for the boom gun, can anyone here help provide that info

[glitterboy2098]

no official weight is given, but using the diagram on Pg73 of RUE we can get an estimate based on the amount of metal in the projectiles.

using that, i calculate it would come to about 10 pounds (5kg) per round if the rods are made of steel.

which also means that the full 1000 round load of the current GB stats weighs about 5 tons. on a 1.2 ton "fully loaded" suit.
(the 100 round bin from the old stats, before it was pointlessly and absurdly inflated, would weigh about .5 ton. still a bit much but less idiotic)

if the things were tungsten, which is the typical metal for high velocity kinetic projectile IRL, it would be around 26 pounds (~14kg) per round.

i couldn't find depleted uranium, but regular uranium would make it 7.15 pounds (3.24 kg) per round.

[Svartalf]

But are tungsten or uranium magnetic? You need a magnetic metal to be propelled by a railgun. Plus, let's be honest, steel is cheaper.
or would the flechettes be steel jacketed for propulsion but with U or W penetrators?

[guardiandashi]

no official weight is given, but using the diagram on Pg73 of RUE we can get an estimate based on the amount of metal in the projectiles.

using that, i calculate it would come to about 10 pounds (5kg) per round if the rods are made of steel.

which also means that the full 1000 round load of the current GB stats weighs about 5 tons. on a 1.2 ton "fully loaded" suit.
(the 100 round bin from the old stats, before it was pointlessly and absurdly inflated, would weigh about .5 ton. still a bit much but less idiotic)

if the things were tungsten, which is the typical metal for high velocity kinetic projectile IRL, it would be around 26 pounds (~14kg) per round.

i couldn't find depleted uranium, but regular uranium would make it 7.15 pounds (3.24 kg) per round.

I believe for all practical purposes "regular" uranium and depleted uranium would weight the same. as the real difference between the two is how much of the uranium is the more radioactive isotope. U235 vs U238 or whatever they are.

depleted uranium has been processed to vastly reduce the "hot" uranium by removing it and keeping the "cold" the "hot" uranium once separated and concentrated is then used as "weapons grade uranium/plutonium" or similar.

[ShadowLogan]

But are tungsten or uranium magnetic? You need a magnetic metal to be propelled by a railgun. Plus, let's be honest, steel is cheaper.
or would the flechettes be steel jacketed for propulsion but with U or Tn penetrators?

Well the flechettes from the Boomgun don't need to be magnetic since they are in a canister when fired.

Hello,

I am trying to find the weight of a single round of ammo for the boom gun, can anyone here help provide that info

As glitterboy2098 pointed out, it isn't listed. The Glitterboy doesn't even have a dry mass to compare to a fully loaded mass (take the difference and divide out the number of rounds) like one could do on (for ex) the Samson. Though I think the individual flechettes of the round are likely comparable to other railgun rounds in terms of mass (and a BG round has 200 flechettes)...

[bobharly]

no official weight is given, but using the diagram on Pg73 of RUE we can get an estimate based on the amount of metal in the projectiles.

using that, i calculate it would come to about 10 pounds (5kg) per round if the rods are made of steel.

which also means that the full 1000 round load of the current GB stats weighs about 5 tons. on a 1.2 ton "fully loaded" suit.
(the 100 round bin from the old stats, before it was pointlessly and absurdly inflated, would weigh about .5 ton. still a bit much but less idiotic)

if the things were tungsten, which is the typical metal for high velocity kinetic projectile IRL, it would be around 26 pounds (~14kg) per round.

i couldn't find depleted uranium, but regular uranium would make it 7.15 pounds (3.24 kg) per round.

That's funny, I came up with similar numbers when I tried to calculate it! And that is why I like math...

I run 1st edition rules so my GB's only have 100 rounds. But when the ammo weighs that much it makes no sense. Furthermore I found the speed of the Sonic Boom for the "BOOM GUN" to be underwhelming compared to the supposed effect. So I opted to go different route.

I increased the velocity to MACH 11 to reduce the Mass. NOW THAT"S A BOOM! The final result is 100 rounds weigh 25 kg or 55 lbs.

.25kg x 3.8km/ps

As far as the barrel size is concerned, that's the outer barrel diameter for the cooling system. It's as good as any other explanation. I figure this thing gets HOT real fast.

[bobharly]

Deleted. Double Post.

[Marcethus]

no official weight is given, but using the diagram on Pg73 of RUE we can get an estimate based on the amount of metal in the projectiles.

using that, i calculate it would come to about 10 pounds (5kg) per round if the rods are made of steel.

which also means that the full 1000 round load of the current GB stats weighs about 5 tons. on a 1.2 ton "fully loaded" suit.
(the 100 round bin from the old stats, before it was pointlessly and absurdly inflated, would weigh about .5 ton. still a bit much but less idiotic)

if the things were tungsten, which is the typical metal for high velocity kinetic projectile IRL, it would be around 26 pounds (~14kg) per round.

i couldn't find depleted uranium, but regular uranium would make it 7.15 pounds (3.24 kg) per round.

That's funny, I came up with similar numbers when I tried to calculate it! And that is why I like math...

I run 1st edition rules so my GB's only have 100 rounds. But when the ammo weighs that much it makes no sense. Furthermore I found the speed of the Sonic Boom for the "BOOM GUN" to be underwhelming compared to the supposed effect. So I opted to go different route.

I increased the velocity to MACH 11 to reduce the Mass. NOW THAT"S A BOOM! The final result is 100 rounds weigh 25 kg or 55 lbs.

.25kg x 3.8km/ps

As far as the barrel size is concerned, that's the outer barrel diameter for the cooling system. It's as good as any other explanation. I figure this thing gets HOT real fast.

Mach 11 seems a bit high. RUE did increase the speed of the round to Mach 5 IIRC though.

[bobharly]

Mach 11 seems a bit high. RUE did increase the speed of the round to Mach 5 IIRC though.

That was my initial thought too! But as I did my homework I learned some interesting stuff. Modern projectile firearms can reach up to 2k km/ps or just under Mach 6. The main cannon from a M1A1 Abrams tank can fire rounds up to 1.7k km/ps or just under Mach 5. Rail Guns that are currently being tested are approaching 3k km/ps.

After reading that I concluded that the Rail guns in Rifts were underrated. I figured the GB boom gun was the pinnacle of Rail Gun technology, so I pushed the speed up to 3.8k km/ps or MACH 11 to represent future technological advancements. It's sci-fi, right? I also liked the idea of MACH 11, since apparently a modern tank round firing at sub Mach 5 does seem to be worth mentioning in the rules as causeing a stunning "Boom" effect.

As another side note, I'm not so sure that rail guns would fire in bursts as that is a lot of heat. The GB boom gun firing the single flechette seems the most realistic based on current readings on the topic.

[J_cobbers]

One thought I have had about this is that the flechettes are made from a non-ferrous material, perhaps a MDC ceramic or polymer, but the casing material is, and that is what accelerates them. Another thought along is that each flechette has a small ferrous component, either a tip, core or base, or perhaps blended with some other materal into the overall material of the body of each flechette, allowing the magnetic forces of the boomgun to accelerate them. This might reduce the mass enough for the 1000 round RUE capacity to make sense.

Or the real secret of the GB technology maybe that the Ammo container actually has a technologically created pocket dimension that allows an unrealistic number of rounds to be loaded and fed to the boomgun without effecting the actual weight of the Power Armor, which is why there is not separate listing for the empty weight. Think about it, totally makes sense as to why they are so hard to build.

[dragonfett]

As another side note, I'm not so sure that rail guns would fire in bursts as that is a lot of heat. The GB boom gun firing the single flechette seems the most realistic based on current readings on the topic.

As far as I have known, the Boom Gun has never fired in bursts. The Boom Gun fires a single "flechette" that holds 200 slugs (similar to a shotgun, but on a larger scale).

[bobharly]

As another side note, I'm not so sure that rail guns would fire in bursts as that is a lot of heat. The GB boom gun firing the single flechette seems the most realistic based on current readings on the topic.

As far as I have known, the Boom Gun has never fired in bursts. The Boom Gun fires a single "flechette" that holds 200 slugs (similar to a shotgun, but on a larger scale).

Correct! I am referring to every other rail gun published for all the other mecha and borgs. (I thought it was a single flechette? I'll have to look that up.)

[guardiandashi]

As another side note, I'm not so sure that rail guns would fire in bursts as that is a lot of heat. The GB boom gun firing the single flechette seems the most realistic based on current readings on the topic.

As far as I have known, the Boom Gun has never fired in bursts. The Boom Gun fires a single "flechette" that holds 200 slugs (similar to a shotgun, but on a larger scale).

Correct! I am referring to every other rail gun published for all the other mecha and borgs. (I thought it was a single flechette? I'll have to look that up.)

to be correct as to my understanding. each of the 200 submunitions is a single Flechette the carrier is a Sabot (meaning shoe) that holds them together as they travel down the barrel, (and some unspecified distance) after leaving the barrel.

the Flechette style rounds means that for all practical purposes it is firing a large number of rods/needles instead of pellets as in a traditional shotgun.

my personal belief is that the whole mass of flechettes and sabot, that is projected should be traveling at closer to mach 10-20 than mach 5 in order to trigger the secondary effects that the boom gun is legendary for.

[ShadowLogan]

While not the Glitterboy's Boomgun, the Shemerian railgun is stated to be similar to the GB BG (flechette canister firing). According to SB1o pg91, the ammo belt has a weight of 30lbs for "220 rounds per belt fed backpack", so each "round" is ~0.14lbs per round.

Shermerian Nation SB lists (pg36 for the 6000 Rail Gun, also repeated on pg56-7 with both the 6k & 4k version):
-5lb ammo clip holding 12 rounds, or ~0.42lbs per round
-30lb ammo backpack holding 220 rounds, or ~0.14lbs per round
-390lb ammo drum holding 820 rounds, or ~0.48lbs per round

[J_cobbers]

While not the Glitterboy's Boomgun, the Shemerian railgun is stated to be similar to the GB BG (flechette canister firing). According to SB1o pg91, the ammo belt has a weight of 30lbs for "220 rounds per belt fed backpack", so each "round" is ~0.14lbs per round.

Shermerian Nation SB lists (pg36 for the 6000 Rail Gun, also repeated on pg56-7 with both the 6k & 4k version):
-5lb ammo clip holding 12 rounds, or ~0.42lbs per round
-30lb ammo backpack holding 220 rounds, or ~0.14lbs per round
-390lb ammo drum holding 820 rounds, or ~0.48lbs per round

But then you have to factor in the empty weight of each ammo holding device. Given the weights, the Ammo Backpack having the lowest average weight to number of rounds held, must by itself not weigh much at all, where as the 12 round clip could be fairly heavy for the number of rounds it holds. Given that, this means that each round must be less than the ~.136lbs for the average weight on the 30lb backpack. If you give the backpack a 1lb empty weight (which is not entirely, but only kind of, unreasonable if it is mostly MDC Fabric) that leaves 29 lbs for the weight of all 220 rounds, or ~.132 lbs per round. Of course this means the 5lb clip with 12 round capacity has a dry weight of ~3.4 lbs, and the 390 lb drum a dry weight of 281.76lbs which makes no practical sense. So then the backpack is obviously under weighted.

So if instead you assume 1 lb of the 5 lb clip is the dry weight, leaving your with .333 lbs per round, which in turn means the ammo drum dry weight is a slightly more sensible 116.94 lbs. At a .333 lb weight, the 220 rounds would be 73.26 lbs plus the weight of the back pack. I think the back pack would be reasonable to weight up to 80 lbs and then just call the original entry a typo

Either way just goes to show you that the writers don't always do their math when making up stats!

Bringing this back full circle the weight of GB rounds, if the weight works out to be the same as the Shermerian rail gun (I'm not looking at it's stats, just purely shooting from the hip here) 1000 rounds in the RUE GB would be 333 lbs, and only 33.3 lbs for the 100 rounds in the RMB GB, neither of which would be too much for it to carry.

Oh and I found a kinetic energy calculator online and plugged in the converted Kg and m/s for .333 lbs (0.1510463 kg) and mach 5 (1715 m/s), and found that would equal 222130.57685875 joules of energy. Now I need a more engineering minded person to tell us how destructive that amount of energy is and if we could consider that as a reasonable expression of MD or not.

http://www.csgnetwork.com/kineticenergycalc.html

[guardiandashi]

While not the Glitterboy's Boomgun, the Shemerian railgun is stated to be similar to the GB BG (flechette canister firing). According to SB1o pg91, the ammo belt has a weight of 30lbs for "220 rounds per belt fed backpack", so each "round" is ~0.14lbs per round.

Shermerian Nation SB lists (pg36 for the 6000 Rail Gun, also repeated on pg56-7 with both the 6k & 4k version):
-5lb ammo clip holding 12 rounds, or ~0.42lbs per round
-30lb ammo backpack holding 220 rounds, or ~0.14lbs per round
-390lb ammo drum holding 820 rounds, or ~0.48lbs per round

one minor quibble is If I remember right the 5lb 12 round clip also includes a small battery charge allowing the gun to be fired without additional power input.

[ShadowLogan]

But then you have to factor in the empty weight of each ammo holding device. ...

Correct, but one could also view that as taking into consideration the mass of the storage device and scaling it for custom ammo sizes. It is not perfect I admit, but it does give a rough idea of what it could be. It also cuts down on the assumed weights. It should also be noted we don't know if the backpack is fabric (yes I know they make MDC fabrics available in Rifts) or a hard shell (RT's ASC has hardshell backpacks for its body armors for ex.).

Either way just goes to show you that the writers don't always do their math when making up stats!

Among other things.

one minor quibble is If I remember right the 5lb 12 round clip also includes a small battery charge allowing the gun to be fired without additional power input.

Not that I'm aware of.

[J_cobbers]

So according to Wikipedia, a the average stick of dynamite creates roughly 1 Mega Joule of energy on detonation or 1,000,000 Joules. Compared to my earlier calculation for a boomgun rail gun round having 222130.5 Joules based on weight of .333lbs, means that isn't probably enough mass, basically equal to a quarter stick of dynamite. I think most MDC structures would probably just laugh at that!
I kinda like the idea that dynamite would be a good starting point for MD. If we know the MD rating for a stick of dynamite, we can figure out roughly how many equal the MD dealt by the boom gun, and work the equations from there to figure out what an appropriate mass for the rounds (the 200 slugs) should be since we already know the velocity.

[bobharly]

So according to Wikipedia, a the average stick of dynamite creates roughly 1 Mega Joule of energy on detonation or 1,000,000 Joules. Compared to my earlier calculation for a boomgun rail gun round having 222130.5 Joules based on weight of .333lbs, means that isn't probably enough mass, basically equal to a quarter stick of dynamite. I think most MDC structures would probably just laugh at that!
I kinda like the idea that dynamite would be a good starting point for MD. If we know the MD rating for a stick of dynamite, we can figure out roughly how many equal the MD dealt by the boom gun, and work the equations from there to figure out what an appropriate mass for the rounds (the 200 slugs) should be since we already know the velocity.

I did not think of a stick of dynamite as a starting point. That's are really good idea, but that's not where I started.

1st edition Robotech on one of the Destroids lists the .50 cal. at 1d4 MD (It also lists the same weapon as 7d6 SDC which I always thought was silly). And in the Southern Cross the Hover Tank's back up weapon, the 32mm Tri-Barrel Auto Cannon at 6d6 MD. So I looked up joules for these weapons and began looking for correlations. The .50 Cal can generate up to 20000 joules and the 30mm from A10 Warthog can generate 201000 joules. So I divide by 50 for SDC or 5000 for MD. That gives me 400 SDC or 4 MD for the .50 cal. And doing the same for the 30mm gives me 40 MD. So that puts me in the right ball park. Plus, a .50 Cal can penetrate over .50" of armored steel plate. And the 30mm can penetrate up to 4" IIRC.

So, if the GB slug weighs 0.25 kg and travels at 2700 mps (Mach 8--Revised from my previous post) it generates 911250 joules, divide by 5000 for 180 MD. 3d6x10 anyone? I was pretty satisfied at this point, but I took it one step further...

Now where the math begins to fail me is when I start looking at real weapons of war, like the main gun on a M1A1 Abrams Tank. That bad boy uses a 10 kg projectile (not including the casing and charge) which travels at 1555 mps. It generates 12 Mega Joules and can penetrate over 8" of laminated/sloped armor IIRC! If I divide by 5000 I get 2400 MD or 4d6x100! At this point I decided that real world weapons are much scarier than fiction...

So I concluded that my formula was nice for small arms and up to power armor/small battaloids. But anything larger than that it really doesn't work as the game is currently balanced. So I took the fiction route and let the details slide so we could play...

So back to the stick of dynamite. It will explode equally in all directions, losing a lot of energy compared to a directional weapon like a bullet. A bullet, though chemically propelled, has much of the energy focused in a single direction (Two if you consider recoil, Three if you consider chamber pressure) and arrives striking with high energy focused on to the small surface area of the bullet. I really like the idea of using a stick of dynamite as a reference point, but I don't know enough math to go beyond where I am currently at.

[dragonfett]

So according to Wikipedia, a the average stick of dynamite creates roughly 1 Mega Joule of energy on detonation or 1,000,000 Joules. Compared to my earlier calculation for a boomgun rail gun round having 222130.5 Joules based on weight of .333lbs, means that isn't probably enough mass, basically equal to a quarter stick of dynamite. I think most MDC structures would probably just laugh at that!
I kinda like the idea that dynamite would be a good starting point for MD. If we know the MD rating for a stick of dynamite, we can figure out roughly how many equal the MD dealt by the boom gun, and work the equations from there to figure out what an appropriate mass for the rounds (the 200 slugs) should be since we already know the velocity.

I did not think of a stick of dynamite as a starting point. That's are really good idea, but that's not where I started.

1st edition Robotech on one of the Destroids lists the .50 cal. at 1d4 MD (It also lists the same weapon as 7d6 SDC which I always thought was silly). And in the Southern Cross the Hover Tank's back up weapon, the 32mm Tri-Barrel Auto Cannon at 6d6 MD. So I looked up joules for these weapons and began looking for correlations. The .50 Cal can generate up to 20000 joules and the 30mm from A10 Warthog can generate 201000 joules. So I divide by 50 for SDC or 5000 for MD. That gives me 400 SDC or 4 MD for the .50 cal. And doing the same for the 30mm gives me 40 MD. So that puts me in the right ball park. Plus, a .50 Cal can penetrate over .50" of armored steel plate. And the 30mm can penetrate up to 4" IIRC.

So, if the GB slug weighs 0.25 kg and travels at 2700 mps (Mach 8--Revised from my previous post) it generates 911250 joules, divide by 5000 for 180 MD. 3d6x10 anyone? I was pretty satisfied at this point, but I took it one step further...

Now where the math begins to fail me is when I start looking at real weapons of war, like the main gun on a M1A1 Abrams Tank. That bad boy uses a 10 kg projectile (not including the casing and charge) which travels at 1555 mps. It generates 12 Mega Joules and can penetrate over 8" of laminated/sloped armor IIRC! If I divide by 5000 I get 2400 MD or 4d6x100! At this point I decided that real world weapons are much scarier than fiction...

So I concluded that my formula was nice for small arms and up to power armor/small battaloids. But anything larger than that it really doesn't work as the game is currently balanced. So I took the fiction route and let the details slide so we could play...

So back to the stick of dynamite. It will explode equally in all directions, losing a lot of energy compared to a directional weapon like a bullet. A bullet, though chemically propelled, has much of the energy focused in a single direction (Two if you consider recoil, Three if you consider chamber pressure) and arrives striking with high energy focused on to the small surface area of the bullet. I really like the idea of using a stick of dynamite as a reference point, but I don't know enough math to go beyond where I am currently at.

I don't think that PB wanted to let the actual tanks in the game do as much damage as their real world counterparts because then at that point it comes down to who fires first.

[bobharly]

I don't think that PB wanted to let the actual tanks in the game do as much damage as their real world counterparts because then at that point it comes down to who fires first.

I agree. In the end we have to remember that it's a game, not a simulation.

[ShadowLogan]

So according to Wikipedia, a the average stick of dynamite creates roughly 1 Mega Joule of energy on detonation or 1,000,000 Joules. Compared to my earlier calculation for a boomgun rail gun round having 222130.5 Joules based on weight of .333lbs, means that isn't probably enough mass, basically equal to a quarter stick of dynamite. I think most MDC structures would probably just laugh at that!
I kinda like the idea that dynamite would be a good starting point for MD. If we know the MD rating for a stick of dynamite, we can figure out roughly how many equal the MD dealt by the boom gun, and work the equations from there to figure out what an appropriate mass for the rounds (the 200 slugs) should be since we already know the velocity.

Did check this by comparing the KE of other known objects/weapons in the game to determine if the energy as any relation to its assigned damage (because I think damages are all arbitrary and with no sense of scale).

Consider this if you use the RUE (or RMB) rules for generic damage on pg 345 for collision and apply it to a round fired from an M-16 using the real world velocity, the damage would not be 4d6S.D as in its stat block, it actually works out to something like 2d8 M.D (or 4d4 M.D). An Ak-47 is 1/2 that, so to would be the .50cal machinegun and 120mm cannon found on the M1A1 tank. Palladium doesn't really have something to consider KE, just velocity/speed or mass/weight not the two working together.

[Axelmania]

I just had a cool idea. Maybe boom gun rounds are relatively light because now they are 1/10 the size. This would explain why suddenly the power armor can hold 1000 instead of 100.

These new light rounds only do 3D6 per shot. Still pretty decent and keeps its amazing range. The 3D6x10 is now a 10 round burst with.reduced accuracy.

[jaymz]

I personally would say the flechettes themselves, like mdc armour, are manufactured using mdc materials and processes. THAT would significantly decrease the weight of each flechette and by extension each "round".