Let me start with this:
I think MJ has something against (although not extreme) different types of bullets.
I am not opposed to bullets having different effects; I am opposed to overly complicating the situation.
Given that these are armor piercing bullets, the assumption is being made that they are specifically good at piercing armor. I think, though, that this is already covered in the fact that they've been given a base lethal damage value. That is, armor piercing bullets do more damage against armor-clad opponents because they do more damage against everything--they will do more damage to an unarmored opponent than an otherwise comparable bullet that is not designed to be armor piercing.
I could have said that armor piercing bullets do ordinary dangerous damage against all targets, but get a +20 sit-mod against any armor. This has some really peculiar effects, though. Suppose I am wearing a bullet-proof vest--vest only. Previous calculations make the cover value of such a vest -12 (because you can be shot in the legs, the vest not covering all of your body). The armor-piercing bullets give a +20 bonus only if the target is wearing armor--which means that the person wearing a bullet proof vest is 8% less likely to be hit by the bullet if he removes the vest.
So say that it eliminates the effects of armor entirely. Now you have an entirely different problem--defining what constitutes "armor" for purposes of this elimination. Armor, under the rules, is cover, but that it moves with the wearer. That is, putting on a suit of armor is the equivalent of having a wall interposed between you and the attacker, but that you can move the wall. Suddenly we have a gun that can shoot through any such cover--including punching holes in neutronium alloy space ship hulls. We make mecha armor from depleted uranium, but it doesn't stop armor piercing bullets.
Any solution to this becomes much more complicated in play. Do you want to make it so that armor piercing bullets penetrate any cover up to the density of the bullet, but has no effect above that? That's a sort of bright-line test that really does not make sense, since the relative density of the two substances should mean increasing resistance of the armor against the bullet. Do you want armor piercing bullets to reduce cover value by a percentage? John wants it to mean that leather and chain and steel plate won't stop his bullets at all, but I'm sure he would agree that three inch thick depleted uranium would. Besides, this would mean that the more resistance a piece of cover has to penetration, the more effective the bullet is at reducing that resistance--that it would reduce the 12% cover of a vest by 1%, the 25% cover of chain mail by 3%, and the 80% cover of a solid uranium wall by 8%.
The question, then, is what really happens when any projectile hits any cover?
The answer is, the cover slows and deflects the projectile to some degree. That means fewer shots actually hit the person behind the cover, and those which do are less effective.
That is best defined by sit-mods.
I could define it by damage (die) mods, but other than the reduced botch effect this really doesn't make that much difference in this scenario. That is, if we're looking at a 60% chance to hit for dangerous damage, our shooter can roll up to 60 and do up to 6 intensities of damage. If we put a -20 sit-mod on that, we have any roll up to 40 is successful, and we can do up to four intensities of damage. Let us instead take a -20 damage mod. That means that any roll up to 60 will still hit, but we will subtract 20 from the roll before calculating damage. all rolls through 20 now do 0 damage, and rolls from 21 through 60 do from 1 to 4 intensities. We have the same effective range of damage as we would with a sit-mod, but a more complicated calculation to derive it. The only real difference in effect is that there is a 6% chance to botch with the sit-mod and only a 4% chance to botch with the damage mod--and I'm not certain that's an advantage, particularly since we have admitted we are using a highly complex technological device in a low tech world with very dangerous ammo.
I suspect it principally falls into the category of having to create details.
Its one of the things that is very hard for a 'generic' game because there are literally a thousand and one different sets of details you need....
Besides no one particularly wants to write 300,000 words. However, it needs to be done....
Also, certain residents of the People's Socialist Republics of the Northeast might have a tiny bit less experience with guns since they are not as free as Real Americans....
Although I've never felt any legal constraint preventing me from owning or using guns, and I have had experience with a variety of firearms (mostly in the Berkshires at my Uncle's place) ranging from flintlocks through rifles and shotguns, I admit readily that I've insufficient experience with or knowledge of guns to adequately address the matter. That is a fair point. The rest, though, I think a bit unfair.
In the Spring before Multiverser went to print, there were several projects envisioned to expand the game. Among them was a detailed combat supplement giving information on hundreds of real and imagined, historic and futuristic, weapons and attack forms in every bias area. We were going to do this with the aid of the employees we would hire with all the money that was going to come pouring into our coffers when our new game took the role playing world by storm.
Not only did that money not come, my partner, who was considerably better informed in and experienced with firearms (military marksmanship ribbons) and weapons (SCA and Marklanders) than I, dropped out of the effort. He had good reasons at the time, and I do not hold any ill-will for that. However, it left the guy who knew very little about real weapons to do whatever was to be done, and a priority at the time on completing a second book of worlds (which took too long as it was) and getting the game promoted on a shoestring.
I'm given to understand that BTRC has published an excellent resource on real weapons entitled Guns, Guns, Guns, and I have long wished I could obtain a copy and find a way to do direct conversions of their numbers to ours without infringing on their intellectual property. I have too many other financial needs to have been able to make that acquisition, so I can neither personally recommend the book nor do the conversion.
The problem of the sit-mod versus a damage modifier is adequately addressed by Scott:
Don't think of the penalty as turning otherwise good hits into misses. Think of it as turning good hits into mediocre hits, turning mediocre hits into cruddy hits, and preventing the hits that would have been cruddy even without the armor from doing any significant damage at all. That's not what the math looks like when you see it first, but that's effectively what the sit-mod is doing.
Because of the single-roll hit-and-damage system, that is what happens--your best shots are reduced in the amount of damage they can do, and the shots that would have been minimal hits are deflected or slowed such that they do no damage.
Part of the problem arises in describing the scene, and part of it comes from Multiverser's (and most games') system of combining all penalties into one. That makes sense, given that when you attempt to turn it around you get all kinds of confusion. In this case, we have the target value, which is already a combination of how well the individual dodges and how tough it is to penetrate his body with an attack, and separately we have the cover value, which is also a combination of to what degree the metal deflects the bullets and to what degree it slows them. I'm trying to give a credible color description to a mathematical result, and in assessing "credible" I'm giving place to the player's sensibilities. He thinks that a bullet of this sort would never be deflected by armor of this sort, even if it caught the edge of the shoulder or something. Thus in my descriptions I did not say that the chain ever deflected a bullet (although if he were shooting at Adam's Spectra Armor I probably would have included deflection in the descriptions). I am not so persuaded, but I'm not going to let that difference of opinion get in the way of our game. The dice say that this bullet missed. It doesn't matter, to anything mechanical within the game, whether it missed because he panicked in his aim, or the target dodged, or the metal chain stopped the bullet; it only matters to the color.
His objection is that the metal chain should never slow or stop a bullet of this sort. Forgive me for saying so, but that is an absurd objection even if your Uncle Bob doesn't realize it. A bullet that hits an unarmored man will hit him harder and faster than one that has to pass through a sheet of metal to get there; it therefore will do more damage. The flip side of that is that an armored man is going to take less damage from bullets which pass through his armor. That is achieved by reducing the probability on the success roll. In other words, this:
I mean if you have a 6 foot by 3 foot piece of paper, and a 6 foot by 3 foot piece of titanium alloy, and you're shooting from the same distance, you have an equal chance to hit both of them. Your chances of hitting the titanium alloy are not reduced, your chance of PENETRATING it is reduced.
...both hits and misses the point. The point is not whether you can hit the six-by-three rectangle; the point is whether you can hit the man standing behind that six-by-three rectangle. If he is standing behind a sheet of paper, that's going to have a negligible effect on your ability to hit him; if he's standing behind a wall of titanium, that's going to have a tremendous effect on it. A steel chain curtain falls somewhere between the two, reducing your chance to hit the man behind it.
Well, I would have made it so that you had the same chance to hit, but a shot that would have done dangerous damage would now only do annoying damage.
This is a
much more severe penalty than the one imposed, apart from being considerably harder to adjudicate fairly. There are, after all, only seven damage categories, and there is quite a range of potential cover. Let's say that each density level of the cover creates one damage category penalty. That would mean that armor made of leather, wood, glass, or bone would create one damage category penalty, some plastics, soft metals, soft stone, and most polymers two, hard metal two to four, hard stone three to four, gems three to five, and sci-fi and fantasy materials like mithril and duralloy three to six. This gives no factor for how complete the cover is; either you have to work out separately whether or not the cover was hit, or you have to give the benefit to anyone wearing as little as a single armband. We now have a system whereby a man carrying a mithril shield can reduce the force of an atomic blast to an annoying attack, which might or might not do one intensity of damage to him.
More to the point, a damage category penalty typically reduces the damage done by half or more. A situation modifier reduces damage by a fraction based on a reduced chance that you would land a "good" hit. If that chance is already very low, it's a significant penalty--but if you're a good shot, the penalty for the armor is a considerably smaller part of the total.
Chain mail would stop a slash from a sword, but a stab would go right in between the links. I used to have a friend that made chain mail vests to sell at conventions. They were great for reducing blunt force trauma (club, mace, ax, sword slash) but a thin sword like a rapier would go between the links and they would have little to no effect at stopping or even slowing it down.
If you want to aim for one of the holes between the links, you're welcome to do so. Chain mail, in my experience, is made of rings between one half and one inch in diameter; since the wire is at least a sixteenth of an inch thick, you're looking at maybe as small as an eighth of an inch hole, through which other links are passing. That's smaller than the diameter of your bullet--which means you can't possibly shoot through the center of the ring without hitting the edges.
So chain mail impedes bullets. It does not stop them--nothing stops anything competely, it just works to make it much more difficult to hit the person behind it.
I hope this answers the problems.
--M. J. Young