Double damage on a charge: why do lances work?

[Scryangi]

1)If a character has a speed of 50 feet, just like a horse, does he deal double damage on a charge with a lance?

2) Would another weapon work? A longspear perhaps? What if he rides by and swings his sword? Would it not have the same velocity?

3) What if a giant puts his weight into impaling someone with his sword, thus mimicking the mass and velocity that the mount would add to a charge?

4) Pounce? I heard that it interacts in a special way with lances. Could someone explain that to me?

Thank you in advance for any input, and I wish you all a nice day.

[Troacctid]

1. Depends. Does he have a speed of 50 feet because he's a centaur? If so, yes. Otherwise, no.
2. No.
3. No.
4. Pounce works when you charge, not when your mount charges. If your mount pounces, it makes a full attack and you can make one attack. If you have pounce, you still only make one attack when your mount charges.

[Ruslan]

1. A lance deals double damage when used from the back of a charging mount. Merely having a speed of 50' is not enough. Edit: being a centaur is also not enough. If you want it to work, feel free to make your own houserule though.
2. No. If you want it to work, feel free to make your own houserule though.
3. No. If you want it to work, feel free to make your own houserule though.
4. Pounce and Lance don't interact in a special way, except perhaps as a rhyme. If you want them to, feel free to make your own houserule though.

[Extra Anchovies]

1) No.
2) No.
3) No.
4) The mount gets a full attack if it has pounce, but you aren't charging so you don't get a full attack. That's part of why there are ways to multiply damage on a charge; instead of multiple normal-damage attacks you get one high-damage attack.

You might be interested in the Q&A by RAW thread for questions like this. A new one just started up; it's stickied at the top of the thread list.

[Lord Vukodlak]

1)If a character has a speed of 50 feet, just like a horse, does he deal double damage on a charge with a lance?
No, only from the back of a charging mout


2) Would another weapon work? A longspear perhaps? What if he rides by and swings his sword? Would it not have the same velocity?
No, those weapons don't have that property.
However the spirited charge feat would allows double damage from the back of a charging mount with any melee weapon (triple with a lance)


3) What if a giant puts his weight into impaling someone with his sword, thus mimicking the mass and velocity that the mount would add to a charge?
No

Lances work the way they do because the rules say the work the way they do. The rules are about capturing an idea of chivalric combat not about a display of physics. If you want an excuse its because TWO creatures are the force behind the attack the mount and the wielder.

[Necroticplague]

1)If a character has a speed of 50 feet, just like a horse, does he deal double damage on a charge with a lance?

2) Would another weapon work? A longspear perhaps? What if he rides by and swings his sword? Would it not have the same velocity?

3) What if a giant puts his weight into impaling someone with his sword, thus mimicking the mass and velocity that the mount would add to a charge?

4) Pounce? I heard that it interacts in a special way with lances. Could someone explain that to me?

Thank you in advance for any input, and I wish you all a nice day.

1.no
2.not unless they specifically say to, no,no, unknown, since combat is an abstraction.
3.nope. still doesn't have the specific property
4.It doesn't, wherever you heard that was incorrect.

[The Evil DM]

1)If a character has a speed of 50 feet, just like a horse, does he deal double damage on a charge with a lance?

2) Would another weapon work? A longspear perhaps? What if he rides by and swings his sword? Would it not have the same velocity?

3) What if a giant puts his weight into impaling someone with his sword, thus mimicking the mass and velocity that the mount would add to a charge?

4) Pounce? I heard that it interacts in a special way with lances. Could someone explain that to me?

Thank you in advance for any input, and I wish you all a nice day.

The physics of D&D are off a lot in some of the cases you mentioned. But in general the reason the lance is so deadly is because it places the mass of the Man and the Mass of the horse behind the point of the weapon.

Doing the same at top speed with a sword has the potential to provide leverage against your arm to break it. (just like if you reach out of a car at about 30 miles an hour to try and hit something) Horsemen don't usually use their sword at full charge speed.

Longspear is a foot weapon and isn't designed for mounted use.

Regarding giants - This is where the size system breaks down when compared to physics. Impact damage is based off Impulse through Impulse-Momentum theorem. Momentum is Mass * Velocity.

If one assumes velocity is equal and realize than an object that is doubled in size in all dimensions has 8 times the mass then a 12 foot tall giant swinging a 8 foot long 32 pound long sword built for the 12 foot tall giant should do 8d8 damage (by physics and assuming all other variables are equal.

looking at real large creatures it is easy to see that larger creatures move slower so maybe the result should be 3d8 or 4d8 but still not consistent with D&D sizes.

Regardless of that. Lances work through mass behind the point of impact.

[Scryangi]

Thank you for the swift responses.

Pounce and charging do work together somehow, as someone asked in another thread. I'm just not certain how to visualize it.: http://www.giantitp.com/forums/showthread.php?416972-Charge-multipliers-vs-crits-amp-or-pounce&highlight=lance

[Atanvarno]

After reading these, I find myself contemplating a character on a sufficiently large mount that they can charge across the mount's back while the mount itself is charging :smallamused:

[Telonius]

1 Edit: being a centaur is also not enough. If you want it to work, feel free to make your own houserule though..

Being a Centaur (http://www.d20srd.org/srd/monsters/centaur.htm) is enough:


Combat
A centaur employing a lance deals double damage when it charges, just as a rider on a mount does.

(It's kind of hidden in the "Combat" section, not under "Centaurs as Characters," where you might reasonably expect to see it).

[Ruslan]

Being a Centaur (http://www.d20srd.org/srd/monsters/centaur.htm) is enough:



(It's kind of hidden in the "Combat" section, not under "Centaurs as Characters," where you might reasonably expect to see it).Cool, good to know.

[Necroticplague]

Pounce and charging do work together somehow, as someone asked in another thread. I'm just not certain how to visualize it.: http://www.giantitp.com/forums/showthread.php?416972-Charge-multipliers-vs-crits-amp-or-pounce&highlight=lance

Pounce and charging work together because Pounce modifies a charge. That's the entire point of the ability. It lets you full-attack on a charge, instead of just making one attack. The question here, is Pounce-Lance interaction. When you're mounted, you aren't charging, your mount is. You can't make the full-round attack because

When you attack a creature smaller than your mount that is on foot, you get the +1 bonus on melee attacks for being on higher ground. If your mount moves more than 5 feet, you can only make a single melee attack. Essentially, you have to wait until the mount gets to your enemy before attacking, so you can’t make a full attack. Even at your mount’s full speed, you don’t take any penalty on melee attacks while mounted.
So your mount uses its full-round action to charge, and might be able to full-attack if your mount has pounce. You, on the other hand, use a standard action to attack once with your lance (which does double damage).

[gorfnab]

2) Would another weapon work? A longspear perhaps? What if he rides by and swings his sword? Would it not have the same velocity?

See: Valorous Weapon Enchantment (Unapproachable East - pg 54)



4) Pounce? I heard that it interacts in a special way with lances. Could someone explain that to me?

There are ways to build a character that can charge/pounce and deal double damage without being mounted. This handbook, Little Red Raiding Hood: My Tale of & Guide to the 3.5 Dragoon (http://brilliantgameologists.com/boards/index.php?topic=7200), has builds designed to do tremendous amounts of damage while charging, both mounted and unmounted.

[Saintheart]

After reading these, I find myself contemplating a character on a sufficiently large mount that they can charge across the mount's back while the mount itself is charging :smallamused:

Also a really interesting idea when you consider WOTC's annoying dictum that the movement of a Scout's mount don't count for triggering skirmish damage :smallamused: :smallamused:

[With a box]

if we have a (halfling with a lance) mount on a human and charge, then the damage doubles?

[SinsI]

Never understood this bonus. A flat +X bonus proportional to the distance charged (and one that always works) on first hit (only) with a Lance-like weapon would be much more logical. Why should it double things like Strength bonus damage?

[Scheming Wizard]

In the middle ages armored knights on horseback were the best weapon around. Obviously in D&D there is magic, griffins, dragons, and beholders so the knight on a horse isn't terribly impressive, but back then they were really something. The mounted combat feats and high damage on the lances is supposed to show why the noble class is in charge and how they are able to protect the peasants who in turn pay tribute to them in food driving the economy. Most adventures take place in dungeons, castles, towers, crypts etc. Basically all places you can't take your horse so even Paladins don't usually buy magical lances and get mounted combat feats.

If they do though they can do some pretty serious damage on a smite evil, mounted charge, critical, and then whatever magical ability is on the lance itself. It unfortunately takes a lot of feats and skill points to pull off though, and Paladins aren't blessed with bonus feats. I think a griffin or dragon mounted rider could really dominate an outdoor adventure though.

[SinsI]

In the middle ages armored knights on horseback were the best weapon around.
Only after development of a high quality Full Plate Armor in 14th century that was impenetrable to arrows and bolts. Before that, longbow archers and crossbowmen were the kings of the battlefield. And since heavy crossbows can be made to penetrate even that kind of armor, mercenary crossbowmen were the best weapon around - at ranges less than 100 meters a crossbow bolt fired via late period medieval crossbow has the same kinetic energy as a 7.62 NATO round!
Those noble armored knights were so scared of peasants with arbalests they even had to resort to using religion to try and outlaw crossbow use against Christians...

So if you want D&D to accurately simulate medieval warfare properties, you need a huge boost to heavy crossbow damage, and not try to provide ridiculous bonuses for knights.

[The Evil DM]

So if you want D&D to accurately simulate medieval warfare properties, you need a huge boost to heavy crossbow damage, and not try to provide ridiculous bonuses for knights.

crossbows in 3.5 are broken. In my games I give them Armor Penetration.

Light Crossbows ignore the first 4 points of armor value of any armor or natural armor on the target, this decreases by 1 point per range category.

Heavy Crossbows ignore the first 8 points of armor value of any armor or natural armor on the target, this decreases by 2 points per range category.

I leave the rate of fire the same because at 6 second combat rounds the ROF is not too unreasonable and the change above helps to improve their effectiveness.

[Saintheart]

Only after development of a high quality Full Plate Armor in 14th century that was impenetrable to arrows and bolts. Before that, longbow archers and crossbowmen were the kings of the battlefield. And since heavy crossbows can be made to penetrate even that kind of armor, mercenary crossbowmen were the best weapon around - at ranges less than 100 meters a crossbow bolt fired via late period medieval crossbow has the same kinetic energy as a 7.62 NATO round!
Those noble armored knights were so scared of peasants with arbalests they even had to resort to using religion to try and outlaw crossbow use against Christians...

So if you want D&D to accurately simulate medieval warfare properties, you need a huge boost to heavy crossbow damage, and not try to provide ridiculous bonuses for knights.

Weeeeeell, by that analysis you'd also need to rule that reloading a crossbow takes about 2 full round rounds or so :smallamused:

One of the main advantages armoured men had was mobility. Men on horseback can maneuver and get to different locations a lot faster than a bunch of archers. That was part of the reason castles started getting built -- because you couldn't conceivably chase a band of men on horseback around the countryside while they burned and pillaged at will. Castles -- I'm looking at Alfred the Great onwards -- became strongpoints from which you could more efficiently organise a defence.

Leaving aside that archers were solid performers against cavalry, a charge of knights was still a bloody terrifying thing to men on foot. Pikes started getting up around the same time as crossbows did, mainly because they could stop knightly charges pretty effectively. Funny you should mention they tried to outlaw the crossbow; the use of Swiss pikemen in the period was deemed a war crime for much the same reasons.

[SinsI]

That's still nowhere near enough. While that allows the crossbows to properly need far less BAB to use (a few weeks is enough to train a good crossbowman, while longbowmen are trained over a lifetime), Strength Bonus should increase their Rate of Fire, and you should be able to buy more powerful crossbows that are slower to reload but have much, much higher damage instead (that's where you should put those multipliers, instead on lances!). And that's not even starting on possible magic application...
Crossbowmen also commonly used two crossbows together with two servants to carry and reload them to increase the ROF (8 shots per minute compared to 3 shots per minute for a lone crossbowman).

The main problem would be that if crossbows are so deadly and easy to use, any enemy would be armed with them, and thus an undetected ambush would massacre any PC party (at least if they are caught flatfooted - so all classes without Uncanny Dodge are royally screwed).

[Spiryt]

Only after development of a high quality Full Plate Armor in 14th century that was impenetrable to arrows and bolts. Before that, longbow archers and crossbowmen were the kings of the battlefield. And since heavy crossbows can be made to penetrate even that kind of armor, mercenary crossbowmen were the best weapon around - at ranges less than 100 meters a crossbow bolt fired via late period medieval crossbow has the same kinetic energy as a 7.62 NATO round!
Those noble armored knights were so scared of peasants with arbalests they even had to resort to using religion to try and outlaw crossbow use against Christians...

So if you want D&D to accurately simulate medieval warfare properties, you need a huge boost to heavy crossbow damage, and not try to provide ridiculous bonuses for knights.

Uh, not really.

You'll find literally couple of European battles from 1000-1300 where 'pesants with crossbows' made any real difference, let alone be 'kings of the battlefield'.:smallconfused:

Late medieval period, with plate armor, was actually the period where things started to look a bit more like what you're describing. So professional bow/crossbow shooters were pretty highly prized and sought.

So it's not really plate armor that made any difference, but complicated social, strategic, deployment etc. changes.


at ranges less than 100 meters a crossbow bolt fired via late period medieval crossbow has the same kinetic energy as a 7.62 NATO round!

No, it doesn't have anything close. Dunno where you have taken this from.

It can, at most, have bit more than ~200 J of kinetic energy. 7.62 NATO rounds will have above 500, even if fired from pistol.

Since it's usually fired from rifle, it will have above 3000, obviously.

[The Evil DM]

That's still nowhere near enough. While that allows the crossbows to properly need far less BAB to use (a few weeks is enough to train a good crossbowman, while longbowmen are trained over a lifetime), Strength Bonus should increase their Rate of Fire, and you should be able to buy more powerful crossbows that are slower to reload but have much, much higher damage instead (that's where you should put those multipliers, instead on lances!). And that's not even starting on possible magic application...

The main problem would be that if crossbows are so deadly and easy to use, any enemy would be armed with them, and thus an undetected ambush would massacre any PC party (at least if they are caught flatfooted - so all classes without Uncanny Dodge are royally screwed).

I play heavily houseruled games with a lot of hold over from old fart D&D.

I had to look at damage to see where I compare. I do increase damage as well compared to 3.5 RAW.

2d6 for light crossbows
2d8 for heavy crossbows

And yes, the players fear crossbow ambushes. Most notoriously are packs of kobolds with light crossbows and dedicated reloader/shield bearers to close up kobold holes as needed.

[Hrugner]

2) Would another weapon work? A longspear perhaps? What if he rides by and swings his sword? Would it not have the same velocity?

3) What if a giant puts his weight into impaling someone with his sword, thus mimicking the mass and velocity that the mount would add to a charge?


2) improvised weapon rules are pretty vague, I think it would be fair to rule that any piercing reach weapon could double as a improvised lance at a -4. Many lances look like spears with a weird grip anyway.

3) There is no mass in D&D as all objects take the same amount of falling damage regardless of size. This gives a universal mass constant, everything merely varies by density and weight. Since there isn't actual mass, the damage increase from size is based purely on the size increase and not relative to the amount of energy exchanged. Sure, this means that objects aren't acted on by an equal gravitic force, but that's just part of D&D's strange alchemy, science is best left at home.

[Sian]

do note that certain classes are able to make a full attack even if your mount is charging: Cavalier, Halfing Outrider (both from Complete Warrior), Kishi Charger (Oriental Adventures), Waverider (Savage Species) and possibly some others.

[JohnDaBarr]

Somewhat related: Do charging feats (Reckless Charge, Shock Trooper etc..) work if charging on a mount?

Also what are the must take feats if one would want to build lancer like character?

[Telonius]

if we have a (halfling with a lance) mount on a human and charge, then the damage doubles?

Only if he shouts out, "Who runs Bartertown?" when he does it.

[lsfreak]

Only after development of a high quality Full Plate Armor in 14th century that was impenetrable to arrows and bolts. Before that, longbow archers and crossbowmen were the kings of the battlefield.

To add to Spiryt's criticism of this idea, mail with proper padding - layers of quilted wool or linen or silk - was pretty much impervious to arrows (and basically everything else) anyways. A lot of the people I've seen do weapons testing fail to take into consideration the significant effect the padding has on the effectiveness of mail. Even if they get the construction of the mail mostly correct (iirc even most moderate-quality riveted mail uses too loose a weave) they just test the mail directly against a backboard or pig carcass rather than mail+gambeson. In fact, a proper gambeson by itself (https://www.youtube.com/watch?v=CULmGfvYlso) is enough to stop an arrow (though probably not without broken ribs).

[Flickerdart]

Even if they get the construction of the mail mostly correct (iirc even most moderate-quality riveted mail uses too loose a weave) they just test the mail directly against a backboard or pig carcass rather than mail+gambeson.
Isn't the other problem with this that a human body is much better at mitigating shock (through being pushed back) than a stationary object? Plus most arrows are going to be coming in at an angle, where their penetrative power is lessened.

[SinsI]

In fact, a proper gambeson by itself (https://www.youtube.com/watch?v=CULmGfvYlso) is enough to stop an arrow (though probably not without broken ribs).
Depends on arrowhead used. Needle bodkin penetrate all types of armor (http://en.wikipedia.org/wiki/Bodkin_point), though they might not be able to deliver lethal wounds.
And gambeson to wear under plate was much thinner than the padded jack they show in the video.

[Necroticplague]

Somewhat related: Do charging feats (Reckless Charge, Shock Trooper etc..) work if charging on a mount?

Also what are the must take feats if one would want to build lancer like character?

No. You aren't charging, your mount is. You're making a normal standard-action attack (unless you have a PRC that lets you make a normal full-attack).

Spirited Charge, Mounted Combat, Mounted Fighting, Power Attack, Monkey Grip (the multiplier actually makes it worth it), knock-down/knockback, are a few I can think of.

[P.F.]

I play heavily houseruled games with a lot of hold over from old fart D&D.

I had to look at damage to see where I compare. I do increase damage as well compared to 3.5 RAW.

2d6 for light crossbows
2d8 for heavy crossbows

And yes, the players fear crossbow ambushes. Most notoriously are packs of kobolds with light crossbows and dedicated reloader/shield bearers to close up kobold holes as needed.

I add a strength bonus; the crossbow uses the crossbow's strength instead of the wielder's. Light crossbow +5; heavy crossbow +10.

On topic, RAW it's debatable whether a mounted charge with a reach weapon even works at all.

[Flickerdart]

On topic, RAW it's debatable whether a mounted charge with a reach weapon even works at all.
It works fine for everything but Small characters on Medium mounts, since a rider occupies any of his mount's spaces.

[P.F.]

It works fine for everything but Small characters on Medium mounts, since a rider occupies any of his mount's spaces.

IIRC the rule is that you occupy all of your mount's spaces, not whichever of them is convenient. Folks I play with interpret


assume that you share your mount’s space during combat

as being the mount's entire space, not any of them. Of course we handwave and/or houserule the issues that creates. And of course I have been wrong before.

[Saintheart]

One off-topic query, but would you guys allow Underfoot Combat to apply as a AC bonus if a Small character was riding a Large mount? The rider is "occupying the same space" as a creature two category sizes larger...

[P.F.]

One off-topic query, but would you guys allow Underfoot Combat to apply as a AC bonus if a Small character was riding a Large mount? The rider is "occupying the same space" as a creature two category sizes larger...

RAW FTW, right?

[Troacctid]

One off-topic query, but would you guys allow Underfoot Combat to apply as a AC bonus if a Small character was riding a Large mount? The rider is "occupying the same space" as a creature two category sizes larger...

You don't need a feat for that. Using your mount for cover is only a DC 15 ride check, requiring no action.

[Necroticplague]

One off-topic query, but would you guys allow Underfoot Combat to apply as a AC bonus if a Small character was riding a Large mount? The rider is "occupying the same space" as a creature two category sizes larger...

Um, typically, a mount is one size category larger than you (i.e, medium humans ride Large horses, small halflings ride Medium ponies). But, i guess if you were riding a disproportionately big mount, than yes.

[Curmudgeon]

One off-topic query, but would you guys allow Underfoot Combat to apply as a AC bonus if a Small character was riding a Large mount? The rider is "occupying the same space" as a creature two category sizes larger...
Yes, this would work. Most such feats require that the other creature be an enemy (example: Confound the Big Folk), but Underfoot Combat (http://archive.wizards.com/default.asp?x=dnd/ex/20050204a&page=3) does not. So with that feat your mount could protect you from attacks, whereas the effect of Mounted Combat (http://www.d20srd.org/srd/feats.htm#mountedCombat) is pretty much the reverse: you protect your mount.

[Genth]

Related question -

A lance is basically a spear with the reinforcements and accessories (i.e. the saddle thing) to let it survive the hit.

Does D&D explicitly say that the 'lance' is only the big conical version? If not, then isn't using a longspear with the saddle and so basically using a Lance?
You can't just pick up a random longspear and start doing double damage on a charge, but you don't need to buy a whole lance - just buy the saddle bit.

[Troacctid]

Lances are indeed conical, as seen in the illustration on page 115 of the Player's Handbook.

Longspears are not lances. They're designed for infantry, not cavalry.

[HurinTheCursed]

My DM ruled Archimede's law doesn't apply in D&D because he didn't want us to take the high-value loot from an underwater dungeon.
D&D rules are already pretty heavy, I wouldn't try to add too much realism or physics because rule complexity slows the game and it mostly hurts mundane who don't need it. But each one his own style of game.

The designer's point of view was probably that nobody would take a lance if all spears had double damage in charge AND set vs charge. A pointy stick used in charge for extra damage probably deserves the martial weapon grade both for relative weapon balance and for credibility.
It seems to me many late medieval polearms had reach, allowed to trip from mount, could be set against charge, could trap opponent's weapon, had both slashing and piercing parts. The swiss pike was a different beast however.
Lance were so effective at penetrating unarmored people that it became an hindrance when armor decreased and they used more hunt spear-like weapons with hilt to remove the blade from a body more easily.

Regarding balance, I'd rather allow minor properties like set vs charge to a custom lance rather than throw multipliers around for each spear-like weapon. It might change little for PC, but any large spear-wielding monster allowed to double damage could suddenly become much more lethal than its CR intended, which might not be what you want if you play a written module.

[Elkad]

Double damage is a traditional but silly way to do it.

Lance should be a 2-handed weapon that can be used 1-handed while appropriately mounted. If charging mounted, damage increases one size category, it's always considered two-handed, and uses the greater of mount or riders strength.

So a random 14str dude goes from d8+3 on the ground to d8+2 mounted (slightly worse due to one-handed use). But when he charges on his 18str horse, it jumps to 2d6+6

Or something like that. Needs fiddling. More damage bonuses for more speed maybe. Maybe it's just always sized to the mount, and you take oversized penalties using it dismounted.

[Necroticplague]

Related question -

A lance is basically a spear with the reinforcements and accessories (i.e. the saddle thing) to let it survive the hit.

Does D&D explicitly say that the 'lance' is only the big conical version? If not, then isn't using a longspear with the saddle and so basically using a Lance?
You can't just pick up a random longspear and start doing double damage on a charge, but you don't need to buy a whole lance - just buy the saddle bit.

A Lance and a Longspear are distinct weapons, and rules for one does not apply to the other. Just as how Spiked Gauntlets and Gauntlets+armor spikes are different weapons with different properties, despite being similar.

[Andezzar]

It can, at most, have bit more than ~200 J of kinetic energy. 7.62 NATO rounds will have above 500, even if fired from pistol.

Since it's usually fired from rifle, it will have above 3000, obviously.Just out of curiosity, which pistol actually fires 7.62x51mm NATO (https://en.wikipedia.org/wiki/7.62%C3%9751mm_NATO)?

[danzibr]

Now I'm picturing a Centaur charger build...

[Necroticplague]

Just out of curiosity, which pistol actually fires 7.62x51mm NATO (https://en.wikipedia.org/wiki/7.62%C3%9751mm_NATO)?

Well, some assault rifles can have their stocks and barrels removed to use the body alone like a heavy pistol....kinda pushing it on that definition, though.

[Fitz10019]

4. Pounce and Lance don't interact in a special way, except perhaps as a rhyme. If you want them to, feel free to make your own houserule though.

Pounce and Lance don't rhyme -- but feel free to make your own houserule.

You need like phonetic syllables to rhyme. Fast and Must do not rhyme. Pounce and Trounce rhyme. Lance and Chance rhyme.

[lsfreak]

Just out of curiosity, which pistol actually fires 7.62x51mm NATO (https://en.wikipedia.org/wiki/7.62%C3%9751mm_NATO)?

None that are serious I'm sure. I've seen videos of at least one, maybe two different handguns chambered in .50BMG (both manually breech-loaded) that were made for giggles.

[Andezzar]

.50 BMG handgun, yikes. My wrist hurts just thinking about it.

[SinsI]

Double damage is a traditional but silly way to do it.

Lance should be a 2-handed weapon that can be used 1-handed while appropriately mounted. If charging mounted, damage increases one size category, it's always considered two-handed, and uses the greater of mount or riders strength.

So a random 14str dude goes from d8+3 on the ground to d8+2 mounted (slightly worse due to one-handed use). But when he charges on his 18str horse, it jumps to 2d6+6

Or something like that. Needs fiddling. More damage bonuses for more speed maybe. Maybe it's just always sized to the mount, and you take oversized penalties using it dismounted.

It doesn't really reflect increased penetration capability. Impulse is "m*v". While "v" is a little low, "m" part can be as high as total weight of the mount and rider, so the total impulse (and damage) could be tremendous. The only problem is that it works both ways, so the same force that penetrates the enemy also hits the rider (though over a far greater area)... Tournament lances had to be replaced after each hit for a reason - and they were made to break for the same reason.
This poses a serious problem - I think if you don't break your spear/lance (or at least don't let it go), you'd have to make a Ride check with DC proportional to damage dealt.
If you do break it, it only deals a preset amount of damage depending on the lance in question and your accuracy.

[Curmudgeon]

.50 BMG handgun, yikes. My wrist hurts just thinking about it.
More like your wrist gets a hairline fracture just thinking about it. .50 BMG in a handgun is ridiculous.