I was reading through my Classic BattleTech RPG rules yesterday and I came across the knockback rules. I hate this optional rule (and its corresponding one in SR). Weapons don't knock you back as they do in the movies. Weapons kill by focusing their limited energy on a single point, thus penetrating the target and shreading up your insides. To get the needed force to "knockback" someone you would need a cannon that would apply the same force to the shooter. The only weapons out there that do that are the recoiless rifles and vehicle mounted weapons. Most of these weapons have a rear exhasut to balance out the force applied to the shooter (eg the Carl G anti-tank gun). I never play with the knockback rules and I wish Fanpro would remove them form their games.

SR4 weapons don't knock you back like they did in previous editions, they knock you down, and then only if you're hurt really bad by them. Don't think of it as the force of the weapon driving you to your knees, but rather then force of the impact combined with the pain and being knocked off balance and it might be easier to stomach.

If not, feel free to remove it from your games, just don't let FanPro know or they'll send the SR Gestapo to your house while you're gaming.

Can bullets not knock you off balance? i've never been shot, so wouldn't know for sure, but it seems like they could.

I like the knockdown rules. It adds a bit of cinema to the games I run. Nothing like describing someone dancing the chaingun cha-cha to bring home how brutal firearms are.

The knockdown rules, when linked with the rules for getting back up, are another way that the new rules protects characters from getting killed without reducing the lethality of the weapons to unrealistic levels, in the same way that the rules about armor changing physical damage to stun do. If you're down and can't get back up, you're a bit safer from gun fire and are more easily overlooked as a threat.

And there's the surprose factor. when you shoot a guy in the chest and he drops, you're apt to assume he's dead and focus your attention elsewhere. When he pops back up you'll be wondering what the heck happened while looking down at the grenade at your feet.

Cool. I didn't mean it alone would knock you down, but that it would knock you off balance, which could in turn cause you to fall. But I'll defer to the more experienced gunmen here, since my experiences are drastically limited.

It is my belief that sometimes, when people are shot, they fall down but are not dead. They may even have trouble standing back up again right away. I think SR4's rule handles this well. It has nothing to do with kinetic energy or momentum, it has to do with, "Oh fuck I'm shot that hurts!!!"

That's how I see it. I like knockdown (I sometimes even remember to use the rule!). But if you don't like it, there's no harm in ignoring it. Game balance isn't really affected much by it.

Almost every (real) gunfight I have seen have showed the person who was shot falling to the ground. That is how i play it, the victims just fall forward on there knees, or sometimes drop there weapon or something like that. It adds a good deal to the game I believe.

If the bullet would otherwise have fully penetrated, then armor theoretically increases the probability of being knocked down through work and impulse. If the probability rounded to zero before, as it does for most small arms, it is highly unlikely this will make a real, observable difference.

Do you propose that, ceteris paribus, spreading the work over a wider area increases the probability of a man being physically shoved to the ground?

Does it increase the probability? Sure, why not. That probability is so low, however, that an increase isn't really going to produce a massive change in the number of people who get physically knocked down by the impact of a bullet.

People do, however, FALL down when struck by bullets, either because their reflexive action is to drop low to avoid getting hit again, because the shock of being hit with a bullet disorients them for a second, or because they were already off-balance and the nudge of a round hitting them combined with the muscles near the point of impact tightening up in a trauma response certainly didn't help.

I've expanded SR's "knocked down" state to include being off balance or disoriented... systemically it handles identically (in that it takes a Simple Action to get rid of the modifier), but fluff-wise it can consist of staggering, being in severe pain, or getting the wind knocked out of you. It flows better with my understanding of the realities of gunfights, and doesn't require me to hack out a piece of the system to make it work.

Eh. I'll use the rule when I switch to a new set of rules. For firearms and most other weapons it'll be a Willpower test to convince your body not to crumple like a piece of paper when you get shot. But to give credit where credit's due, it was someone else who came up with the rule.

If you just say "someone else" you're only disavowing credit, not actually giving it where it's due.

It's not "not with me." Aside from that, since he doesn't read DS and no one else on DS knows him, it doesn't really matter.

Honor always matters.

If he was a white guy you found a fraud.

I like the knockback rules. I describe it as both of an "oh shit, I've been stabbed!" sort of thing, and also as a cinematic device (having a guy get blown across a room by a shotgun is just plain cool); it varies on the situation. The key thing is to make sure everyone is having fun. If everyone in the group hates a rule (or if you're GMing and it's giving you a headache), just ignore it. Problem solved.

On another note, I've always wondered why people even bother complaining about a rule they don't even use in the first place. It's not like it's affecting their game.

In one of the latest episodes of MythBusters (airs on Discovery) they proved that you can not be knocked back by any weapon. Even the 50cal they shot only caused the pig target (to represent a human) to just fall down. A shotgun couldn't even knock the pig off the hook. As for crumpling under the pain, that would happen from your wounds more quickly then the pain from the bullet.

The benefit of the knockdown rule as written is its ease of application. No extra rolls or complex equations, just a quick number to check that adds another little complication and obstacle in combat. Is it realistic? Almost certainly not. But it's better than, for example, having to make regular "pain resistance" checks based on your current level of injury.

Mostly, however, it's just a question of style. (My style, for example, might well involve one of the many mooks getting shot and flying back off a ledge as a result, simply because that's the sort of imagery I like.)

so, by the time something can lift you of your feet, it will have enough energy in it to basicly take you apart, bone by bone?

With firearms, definitely. It will usually also be a massive explosive projectile.

What about knockback from explosive and EX-explosive rounds. Surely there is concussive forces involved as the shell detonates on the target sufficient to knock someone back.

If the projectile in question is much larger than .50 BMG bullets or shotgun slugs, it may be sufficient to push someone off-balance. Of course, at that point the momentum of the projectile itself becomes quite considerable. With handguns and nearly all rifles, though, the actual amount of explosive would be minute. For example, the Mk 211 Mod 0 .50 BMG pyrotechnically initiated explosive round has a whopping 13 grains (less than 1 gram) of Composition A-4 in it. You can get more *bang* out of an M-80.

This thread has caused two thoughts to form in my head.

#1. The image i see when reading about this discussion is that bank robbery where those two crazy dudes were dressed up in full body armor and had armor pierceing automatic weapons and had that huge shoot out with the cops. They never even got dropped to their knee's.

#2. How fast do spells travel. Why arent there any magic spells that have -AV modifiers. Surely i can focus my magic into the size of a pinprick and completely bypass armor. Were talking physical spells here, obviously you dont need this with mana spells.


Anybody who brings up realism in arguments in games should be slapped repeatedly. Hello, you just got your left arm dissolved by an acid spell and a dragon is munching on your leg and your worried about whether or not you would actually fall over or get knocked back by a bullet ??

I like the reply some people said about it just making their gaming experience more fun. Thats what its suppose to be about. its not suppose to be a perfect mirror of the real world. If you throw on a bath robe and run outside and try to cut your car in half with your battery operated light saber and it breaks would you be mad?? Then why get mad over making the bad guys fall over or go flying after being shot sometimes??

It's pretty easy to do, it just takes a little engenuity while building your self-stabber machine. Or a really sick and twisted bastard of a friend to help you out.

You know, I love Mythbusters, but that episode mentioned before always bothered me.

They tested the gun-knockback theory by hanging a pig on a chain. If human beings were held on a chain we would never fall either, we would swing....which the pig did do. I never felt that episode was good except for the fact thatI got to watch them shoot up a pig carcass.

Now, if they could have balanced the pig off of the ground, I'm sure it would have fallen. That still wouldn't be accurate, but better in my mind.

they did a retake, that time with buster (their crash test dummy) in a bulletresistent vest...

still, same result, only the shotgun was able to get him to fall of the hook.

think of the knockdown this way:

whats the first thing you do when you touch something hot and didnt expect it? the built in human reaction to pain is to try and get away from it.

so its fully possible to how "ouch!" followed by "oh shit!" and then fall over. or atleast trip or similary end up in a less then optimal stance that you need to recover from...

given that the SR combat system do not have any modifiers for being between standing and prone, prone is the next best thing to simulate that effect...

oh and i belive one the bankrobbers that abbadon talks about got knocked over and failed to get up because the armor was restricting his ability to move. how he got knocked over i dont recall...

ah, thanks for the update. i only have some vague memorys of some low quality helicopter camera shots with one guy on his back...

I'm not saying testing that stuff on a hanging pig carcass is a reasonable model, but fortunately in this case the results mesh with reality and the conclusions were correct.

Now maybe my understanding of the physics here is way off, but I think that the punch actually transfers more energy than a bullet. The bullet starts with more kinetic energy no question, however the bullet also hits the body, goes through, and finishes with a lot more energy too. Whereas a fist has greater mass then a bullet, but much lower velocity and therefore lower kinetic energy, fists don't usually travel through a body and so pretty much come to a stop when they hit one. Hence if Force = Mass x Acceleration and (to make math easy these aren't even close to real numbers I'm sure) you have a 1g Bullet moving at 500m/s when it hits the body and it exits at 300m/s it has transferred about .2 Newtons of force However a 1kg Troll Fist Beginning at 5m/s and ending at 0m/s has transferred 5 Newtons of force. Again while the numbers aren't accurate that's what I believe the principle at work is, hence I'd throw my vote for: Knockdown tests make much more sense for melee combat than for procjectiles, and if you do use knockdown for projectiles it's more likely to be as a result of shock or pain than actual tranfer of physical energy.