Reworking the Rail Gun

[Killer Cyborg]

It's a take off of one of the problems that was faced with the 9mm round, IIRC. The round moved too fast, thusly causing minimal damage to the target. So they slowed the round down and the result is a nice, nasty wound.

Through-and-through penetration is generally undesirable in combat; as it leaves the target largely unaffected.

Of course, there is something to be said for shooting a large metal spike, ball, or ring at such high speeds that the person it hits explodes...

[Killer Cyborg]

Of course, there is something to be said for shooting a large metal spike, ball, or ring at such high speeds that the person it hits explodes...

Of course there is. The was a temptation for making it able to do that, I admit. But it wouldn't be much fun for PC's if fighting with a SAMAS caused them to explode after a melee of combat

It's not ever fun getting shot by any actual weapon.
Moral of the story: Don't Get Shot...

[grandmaster z0b]

I was thinking of giving Rail Guns the same rules as Armour Piercing missiles; x2 damage on a roll of 18-20 with bonuses, x3 natural 20.

[Braden Campbell]

if there were decent canon rules for armour piercing weapons...you would see railguns all over the place.

Our house rules basically said that lasers, particle beams, and plasma did damage to one's armour.

Railguns did damage to one's armour, and an equal amount of damage (in SDC/HP) to the person inside. made the PCs think twice about rushing a machinegun nest...

[RainOfSteel]

While I was leafing through my books idly trying to find a man-portable rail gun that was useful, I came to a disheartening conclusion: the rail guns are basically useless when compared to the other weapons listed in the same book.

Range, damage, cost, weight-wise, they tend to do far less bang for their buck than their energy counterparts. So why do they even exist?

Well, if you're deploying some real tank guns, then obviously there is a reason to have them.

Why mount a rail gun on a tank when a particle cannon would be far more cost-effective and have comparable range with greater damage capacity?

So in an effort to make the rail guns actually useful, I've decided on a few adjustments.

First, I admit that my grasp of ballistics is limited and my physics is rusty.. but this is nonetheless a work in progress.

Now, one thing to bear in mind is that the rail guns, despite how they operate, are really nothing more than high-tech cannons. They take a slug, fire it a high velocities and to smack into some poor, unsuspecting schmuck. However, there's a problem with bullets that have high velocities; at such speeds there's a tendency to pass through the target without imparting much energy onto it.

I take it you've never seen footage of a tank being hit by a high-caliber AP penetrator?

60 ton tanks buck like they've been hit by Thor's hammer.

Ten-ton turrets can be sent flying if the AP round is shot-trapped into the turret ring.

Severe damage can be inflicted on the occupants of the tank due to the pressure waves and the flying metal debris shower from the penetration.

The result is just a hole and not much damage as the round travels onwards until it finds something forces it to stop (a harder target or it's momentum drops until such a point that soft targets can be hit). This is the same reason why armor piercing rounds aren't as effective on lightly armored vehicles like APCs; the round just zips through and little damage is done.

Um, do you have some cites for that? If an APC were hit by: 120mm Tank Gun KE Ammunition, it would be post-toastied.

Effective range/10 is the maximum amount of MDC penetration. In other words, the C-40R (MRB; p226) could travel through up to 400 MDC of armor before it 'stops' when traveling at maximum velcoity.

Effective Range/5 is the maximum distance at which the round can penetrate without stopping.

The trouble with this is that too many small guns have the same range as big guns, giving some very strange penetration comparison problems.

[Killer Cyborg]

I was thinking of giving Rail Guns the same rules as Armour Piercing missiles; x2 damage on a roll of 18-20 with bonuses, x3 natural 20.

That could make things interesting....

[Kalinda]

The only real issue I have with railguns is that with most of them 75% or more of the burst misses when you shoot something. Compare the damage for 1 round to the damage for a burst on just about any railgun and you end up concluding that everything behind/around the target is full of holes...

I've been toying with the idea of adjusting the damage for all the railguns to reflect a 50-75% hit ratio, which would make them much more desirable. (although honestly I've never had a problem with players not using them in my games. once you've tried to fight a battle magus with Impervious to energy, you tend to see the value in slugthrowers.)

[Dead Boy]

... rail guns are basically useless when compared to the other weapons listed in the same book. ... Range, damage, cost, weight-wise, they tend to do far less bang for their buck than their energy counterparts. So why do they even exist? Why mount a rail gun on a tank when a particle cannon would be far more cost-effective and have comparable range with greater damage capacity?

Why? I can think of three good reasons why rail guns are worth the load.

1) Economics ranks up there. For instance, take an NG-P7, a 1D4x10 weapon just like the NG-202 or C-40R. It gets 8 shots out of a standard e-clip which costs 1200 to 1500 credits to recharge. Let's split the difference and call it 1350. That comes out to 168.75 credits per 1D4x10 MD blast. A rail gun that produces the same damage uses 40 rounds of ammo, with each round only costing half a credit. That comes out to only 20 credits for the same amount of damage per shot. That's an 800% savings on every squeeze of the trigger!

2) Only kinetic weapons may use the optional Knock Down rules. And though a pulse laser may seem more high-tech and sexier, a burst of steel (actually the material is still under debate, though personally I like tungsten) has the canon rules behind it to lay some one on their butt. Not only does this momentarily stop their movement if on foot, but it also costs that person the initiative and dogs them one melee attack/action to recover. For the actual rules see the RGMG, pg. 35.

3) Purely energy weapons like lasers, particle beams and ion beams have poor anti-magic characteristics. This is because of the the common-as-dirt defensive spell Impervious to Energy. But use a rail gun and all your magical worries are (mostly) gone. A hard hitting rail gun slug does the same damage whether it goes up against the Imp. to Energy spell, laser resistant armor, or whatever. The only thing it can't hurt are Elementals.

Effective range/10 is the maximum amount of MDC penetration. In other words, the C-40R (MRB; p226) could travel through up to 400 MDC of armor before it 'stops' when traveling at maximum velcoity.

Effective Range/5 is the maximum distance at which the round can penetrate without stopping.

Uh, you're actually making your rail guns rounds punch right through everything to that extent? Hell, if that's the case what's to prevent the players or bad guys to do Called Shots to the head all day long and go for the instant kill? You may want to really reconsider that one.

When a round penetrates without stopping, it does no more than 1MD to 'hard' targets or 1d10 SD/HP to 'soft' targets.

Not that I'm disagreeing with this by itself in principle ... a rail gun slug should only do SDC to an unprotected person ... but bear in mind that a .50 BMG too is a hard hitting but slower round, and as of RUE it does 7D6 SDC per round. You might want to up that one for consistancy's sake.

[grandmaster z0b]

I prefer (and already use) Kalinda's suggestion of upping the amount of rounds that hit, or just applying the canon Armour Piercing rules from RUE and add them to railguns.
As far as figuring out the amount of rounds that hit for example a SAMAS rail gun, you can;

A. roll 1d4 to see how many shots out of the 40 round burst then times that by another 1d4 for damage (max damage 160 MDC).

B. Usually %25 of the burst hits, increase that to %50 if the roll to hit was 5 over the defenders roll (or 8 if no dodge), %75 if 10 over and %100 if 15 over.

eg. a SAMAS shoots at another SAMAS, rolls a 15 the other tries to dodge and rolls a 13, the damage is normal (1d4x10) %25 of the burst hit.

but if the SAMAS has a surprise attack in the back of the other SAMAS and rolls an 18 then %75 of the burst would hit (3d4x10 as there was no dodge the straight to hit number was used in this case 8, if it had been a called shot {12} then it would have been only %50)

confused?



Edit: maths

[Killer Cyborg]

The only real issue I have with railguns is that with most of them 75% or more of the burst misses when you shoot something. Compare the damage for 1 round to the damage for a burst on just about any railgun and you end up concluding that everything behind/around the target is full of holes...

I've been toying with the idea of adjusting the damage for all the railguns to reflect a 50-75% hit ratio, which would make them much more desirable. (although honestly I've never had a problem with players not using them in my games. once you've tried to fight a battle magus with Impervious to energy, you tend to see the value in slugthrowers.)

You could try counting them as heavy machineguns under the original burst rules (Rifts, p. 34), only they fire even faster and can unload a "full clip burst/spray" in 1 attack. Hypothetical clip of 40 rounds.

Short Burst: four rounds, 2d4 MD
Long Burst: thirteen rounds, 1d4x5 MD
Full Clip: 40 rounds, 1d4x20 MD.

This would also allow for sprays, something that railguns should be able to do:
Short Spray: 4 rounds, normal damage, 1d4 targets.
Long Spray: 13 rounds, normal damage, 1d8 targets.
Full Clip Spray: 40 rounds, x2 damage, 2d8 targets.

[Dead Boy]

E-clips can also be recharged for free; Colonial HL, for example. Or anyone with the appropriate skill and access to a nuclear power plant. So it's not just about economics.

Not everyone has access to a nuclear power supply and skills to make a make shift recharger. And the commercialy available recharger (in Merc Ops) isn't widely avaialble.

And you also forget that a rail gun requires three people, is large, bulky, and a lot harder to get your hands on.

If you're not a borg or heavy-lifing RCC, then there are other options. For example there's the NG-303 that only weighs 25 pounds and does OK damage. Alterntely there's also the NG-50R which weighs about as much.

2) Only kinetic weapons may use the optional Knock Down rules.

Please, read those rules. Line one specifically mentions 'energy blasts'...

Damn! You're right. Ok, then look at it this way. Which is easier, a lengthy complicated and potentially unbalancing House Rule like the one you're proposing, or just House Ruling that "energy blast" part out of the the Knock Down rules to give rail guns more significance?

... if that's the case what's to prevent the players or bad guys to do Called Shots to the head all day long and go for the instant kill? You may want to really reconsider that one.

Well, a shot to the head would be -6 -8, so hard to do anyways. But the way it's supposed to work out is that the MDC penetration drops off at a rate of about 1MDC for every 2 feet (something I didn't word properly, I admit)... so at 800ft, you're gonna be able to penetrate zip. At 500ft, you'd be able to go through about 150MDC.. etc.

WP bonuses can greatly off-set that penalty, so it's worth the risk to score the ever-coveted "one shot, one kill". And also the vast majority of combat takes place well inside of 500 feet anyways, so that really isn't much of a limitation.

I can handle that how about 8d6 SDC then?

Works for me. Personally House Ruled it into doing 1/10th the normal damage against "soft targets", which puts a single round at 1D4x10 SDC, which darn near the same as 8D8. The 1/10th rule also makes it easier to handle burst fire as well regardless of how many dice are used.

[Jefffar]

Railguns were a great beneficiary under my house rule alternate damage system, EDC.

Basically EDC was an intermediate damage level between SDC and MDC. 100 SDC = 10 EDC = 1 MDC was the ratio. I reduced most of the "personal" level MDC including body armour, hand held weapons, power armour, cyborgs, minor supernatural beings, low powered magic, non armoured vehciles and the like to EDC.

Railguns, even man portable ones, remained MDC. So did canons and most explosives.

So suddenly, that SAMAS Railgun doing 1D4 MDC on a single round or 1D4x10 MDC for a burst is going against targets whose armour is now between 5 and 10 MDC or are clad in pwer armours of 20 to 50 MDC.

I changed the burst rules too so now isntead of the 1D4x10 per burst, the SAMAS railgun (and all other bursts) score 1 hit for every point above the number required to hit the target (ie 5, 8, 12 or the target's dodge roll dependign on circumstances). So a SAMAS firing a burst at a target that was dodging on a roll of 15 and the SAMAS strike was 18 would score 3 hits, or 3D4 MDC.

Finally I tossed in some recoil penalties for when the gun was cranked up to full auto. I also cut the ammo capacity of most railguns by about half.

The result is that 1 or 2 SAMAS rounds will devastate a character in body armour, but unless the SAMAS is taking aimed shots, a dodging character is unlikely to be hit more than once every couple of rounds. Meanwhile the same SAMAS fighting a large vehcile (which can't dodge effectively) can unload large bursts that will mostly hit, and will shread any vehicle that isn't armoured.

The results are 1) Characters respect railguns much more 2) Characters use simultaneous strike much less 3) combat goes faster 4) players are more careful about when, where and how they get into combat.

[Scooter the Outlaw]

You could try counting them as heavy machineguns under the original burst rules (Rifts, p. 34), only they fire even faster and can unload a "full clip burst/spray" in 1 attack. Hypothetical clip of 40 rounds.

Short Burst: four rounds, 2d4 MD
Long Burst: thirteen rounds, 1d4x5 MD
Full Clip: 40 rounds, 1d4x20 MD.

This would also allow for sprays, something that railguns should be able to do:
Short Spray: 4 rounds, normal damage, 1d4 targets.
Long Spray: 13 rounds, normal damage, 1d8 targets.
Full Clip Spray: 40 rounds, x2 damage, 2d8 targets.

I always thought railguns should be burst/spray capable. It would add a lot to the strategy on ammo division and the like; it would also, overall, make railguns seem different from the other weapons (something Rifts weapons desperately need). One thing I would recommend, though, is instead of using the quarter/half/full-clip system, I'd probably use a preset number of rounds per railgun. If anybody has seen the Advanced Ranged Combat Rules from Rifter #11, that's the kind of thing I'm talking about.

For example, you can fire a single shot for 1 M.D., and then for every 5 rounds you burst in an attack you can add a D6 or something to your attack. So, for a 40 round burst, you'd be firing 8D6--not half bad, and certainly makes the weapon a lot more interesting.

Different guns would have different cyclic rates, too, governing how much ammo they could dump per action. One could fire maybe only 20 rounds per action, while another could shoot off maybe 40 or 60. It'd be another way to differentiate the weapons from one another. This could also be used to designate some weapons as being better as bullet hoses across wide areas and others serving as anti-armor weapons--perhaps a lower cyclic rate and higher damage would be good for gunning down robots, tanks, etc. while high rate one would be good for employing pinning fire against infantry?

But otherwise, my group has always found railguns quite useful--as previously said, they're just about the only thing good against some mages. Not only that, a lot of them have excellent ranges and are pretty cheap to operate.

[Gabriel_V]

Something that came to mind while reading RUE was to give railguns the same advantage that Armor Piercing missiles get. In other words, if they strike roll (with bonuses) is 18 or higher, the railgun does double damage.

[Dead Boy]

NG-303? 50R? Neither of which are listed in the GMG or any North American book I've read so far... where didja find 'em?

They're new. Check out the new book, Merc Ops

Railguns were a great beneficiary under my house rule alternate damage system, EDC.

Basically EDC was an intermediate damage level between SDC and MDC. 100 SDC = 10 EDC = 1 MDC was the ratio. I reduced most of the "personal" level MDC including body armour, hand held weapons, power armour, cyborgs, minor supernatural beings, low powered magic, non armoured vehciles and the like to EDC.

I thought up something virtually identical I called KDC (for Kilo Damage Capacity), but never actually implemented into play. Out of curiosity, what does the "E" in EDC stand for?

I changed the burst rules too so now isntead of the 1D4x10 per burst, the SAMAS railgun (and all other bursts) score 1 hit for every point above the number required to hit the target (ie 5, 8, 12 or the target's dodge roll dependign on circumstances). So a SAMAS firing a burst at a target that was dodging on a roll of 15 and the SAMAS strike was 18 would score 3 hits, or 3D4 MDC.

Ya know, that's a really good idea. Given that RUE leaves us with no contemporary set of burst rules this is a very viable option. Before reading this I was thinking of calling for even numbered bursts to be called and then have a corresponding die rolled to determine the number of hits (i.e. a burst of 4, roll for 1D4 hits; a burst of 10 gets 1D10 hits; a burst of 16 gives you an excuse to buy a 1D16...). Basically, if there's a die for it (3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 24, 30) you can do a burst of that many shots.

I'll have to tinker with things and see what works best for me.

[Jefffar]

I thought up something virtually identical I called KDC (for Kilo Damage Capacity), but never actually implemented into play. Out of curiosity, what does the "E" in EDC stand for?

Enhanced Damage Capacity. I also changed SDC to Standard Damage Capacity.

Ya know, that's a really good idea. Given that RUE leaves us with no contemporary set of burst rules this is a very viable option. Before reading this I was thinking of calling for even numbered bursts to be called and then have a corresponding die rolled to determine the number of hits (i.e. a burst of 4, roll for 1D4 hits; a burst of 10 gets 1D10 hits; a burst of 16 gives you an excuse to buy a 1D16...). Basically, if there's a die for it (3, 4, 5, 6, 7, 8, 10, 12, 14, 16, 18, 20, 24, 30) you can do a burst of that many shots.

I stole the idea from BESM.

Your idea has merit but
1) It's more die to roll than my system
2) It makes it all luck, there's no room for player skill. In mine a player who is a better shot is going to score more hits. In yours it doesn't matter if they are a 10 th level commando or first level saloon bum, they have the same chance for extra hits.
3) Similarly, there si no skill on the aprt of a target to avoid extra damage. In mine a target with a good dodge bonus (ie a juicer) will be hit by less rounds even when the shooter rolls a hit because the difference between the juicer's dodge and the shooters strike will typically be less.

I did some rules with burst length too.
Short burst = 1 to 5 rounds and has light recoil penalties for recoiling weapons.
Medium Burst is 6 to 15 rounds and has medium recoil penalties for recoiling weapons. In a medium burst the number of hits are doubled.
Long Burst is 16 to 30 rounds, counts as 2 melee attacks and has heavy recoil penalties. In a long burst the number of hits are tripled.
Extended burst: every additional 20 rounds or fraction thereof continuing a long burst adds 1 melee attack and 1 more to the number of hits multiplier.

For example, someone who wants to extend a long burst out to a total of 100 rounds (30 + 20 +20 +20 +10 = 100, so 4 extensions) would use 6 melee attacks and suffer heavy recoil penalties but for every point above required roll to hit the shooter will hit with 7 rounds.

Oh, and for obvious reasons, you can't hit with more rounds than you fire and you can't fire more rounds than you have available.

[RainOfSteel]

I take it you've never seen footage of a tank being hit by a high-caliber AP penetrator?

60 ton tanks buck like they've been hit by Thor's hammer.

Ten-ton turrets can be sent flying if the AP round is shot-trapped into the turret ring.

Severe damage can be inflicted on the occupants of the tank due to the pressure waves and the flying metal debris shower from the penetration.

The above is a quote by me. Could you please edit my user name into that?

[RainOfSteel]

Sure, got a comment by an actual tank operator who happens to frequent these boards:
[...]

BTW, I didn't mention "sucking" of things "out the other side" by AP rounds, only a pressure wave.

As for APDSFS lack of effectiveness vs. softer targets (other than helicopters, which I already knew about), I'll have to do some more studying.


Sincerely,

Chris O.

[grandmaster z0b]

There have been some great burst rules here so I thought I'd summarize what we have so far:

I prefer (and already use) Kalinda's suggestion of upping the amount of rounds that hit, or just applying the canon Armour Piercing rules from RUE and add them to railguns.

As far as figuring out the amount of rounds that hit for example a SAMAS rail gun, you can;

A. roll 1d4 to see how many shots out of the 40 round burst then times that by another 1d4 for damage (max damage 160 MDC).

B. Usually %25 of the burst hits, increase that to %50 if the roll to hit was 5 over the defenders roll (or 8 if no dodge), %75 if 10 over and %100 if 15 over.

eg. a SAMAS shoots at another SAMAS, rolls a 15 the other tries to dodge and rolls a 13, the damage is normal (1d4x10) %25 of the burst hit.

but if the SAMAS has a surprise attack in the back of the other SAMAS and rolls an 18 then %75 of the burst would hit (3d4x10 as there was no dodge the straight to hit number was used in this case 8, if it had been a called shot {12} then it would have been only %50)

You could try counting them as heavy machineguns under the original burst rules (Rifts, p. 34), only they fire even faster and can unload a "full clip burst/spray" in 1 attack. Hypothetical clip of 40 rounds.

Short Burst: four rounds, 2d4 MD
Long Burst: thirteen rounds, 1d4x5 MD
Full Clip: 40 rounds, 1d4x20 MD.

This would also allow for sprays, something that railguns should be able to do:
Short Spray: 4 rounds, normal damage, 1d4 targets.
Long Spray: 13 rounds, normal damage, 1d8 targets.
Full Clip Spray: 40 rounds, x2 damage, 2d8 targets.

Railguns were a great beneficiary under my house rule alternate damage system, EDC.

Basically EDC was an intermediate damage level between SDC and MDC. 100 SDC = 10 EDC = 1 MDC was the ratio. I reduced most of the "personal" level MDC including body armour, hand held weapons, power armour, cyborgs, minor supernatural beings, low powered magic, non armoured vehciles and the like to EDC.

Railguns, even man portable ones, remained MDC. So did canons and most explosives.

So suddenly, that SAMAS Railgun doing 1D4 MDC on a single round or 1D4x10 MDC for a burst is going against targets whose armour is now between 5 and 10 MDC or are clad in pwer armours of 20 to 50 MDC.

I changed the burst rules too so now isntead of the 1D4x10 per burst, the SAMAS railgun (and all other bursts) score 1 hit for every point above the number required to hit the target (ie 5, 8, 12 or the target's dodge roll dependign on circumstances). So a SAMAS firing a burst at a target that was dodging on a roll of 15 and the SAMAS strike was 18 would score 3 hits, or 3D4 MDC.

Finally I tossed in some recoil penalties for when the gun was cranked up to full auto. I also cut the ammo capacity of most railguns by about half.

The result is that 1 or 2 SAMAS rounds will devastate a character in body armour, but unless the SAMAS is taking aimed shots, a dodging character is unlikely to be hit more than once every couple of rounds. Meanwhile the same SAMAS fighting a large vehcile (which can't dodge effectively) can unload large bursts that will mostly hit, and will shread any vehicle that isn't armoured.

The results are 1) Characters respect railguns much more 2) Characters use simultaneous strike much less 3) combat goes faster 4) players are more careful about when, where and how they get into combat.

Something that came to mind while reading RUE was to give railguns the same advantage that Armor Piercing missiles get. In other words, if they strike roll (with bonuses) is 18 or higher, the railgun does double damage.

Yeah that was my idea too, see above.

I did some rules with burst length too.
Short burst = 1 to 5 rounds and has light recoil penalties for recoiling weapons.
Medium Burst is 6 to 15 rounds and has medium recoil penalties for recoiling weapons. In a medium burst the number of hits are doubled.
Long Burst is 16 to 30 rounds, counts as 2 melee attacks and has heavy recoil penalties. In a long burst the number of hits are tripled.
Extended burst: every additional 20 rounds or fraction thereof continuing a long burst adds 1 melee attack and 1 more to the number of hits multiplier.

For example, someone who wants to extend a long burst out to a total of 100 rounds (30 + 20 +20 +20 +10 = 100, so 4 extensions) would use 6 melee attacks and suffer heavy recoil penalties but for every point above required roll to hit the shooter will hit with 7 rounds.

Oh, and for obvious reasons, you can't hit with more rounds than you fire and you can't fire more rounds than you have available.

[/u]