I'm looking at rules for armored combat; I'm trying to get some basic idea of what armored combat is really like in terms of assessing the various rules sets.

I don't know much about modern armored combat, so I've come here, hoping someone can set me straight

I'm not exactly sure how to even ask the right set of questions, so here's my unstructured thoughts:

I figure the odds of hitting an immobile, fully visible target, even at long range is pretty close to 100% under anything approaching normal conditions (in other words, I'm guessing that with modern Fire Control Systems, armored vehicles essentially don't miss).

My experience with video games suggest that moving targets get harder to hit -- but I have no idea how big a deal this is.

In the movies driving skill is a good defense against being shot by a tank gun -- in reality can a good driver, moving evasively, make himself significantly more difficult to hit?

My guess is that driving evasively means hiding behind cover, which I bet would make you harder to hit -- but if a target is out in the open, driving evasively, is it really that much harder to target / hit?

And how much harder is harder? Would a world-class driver (in GURPS terms, say 18- skill) reduce the chances of being shot from 100% to 50% or even lower?

One other data point: I've seen statistics that suggest that the number of rounds-fired-per-kill is pretty high. That might imply that there's a whole lot of missing going on, but I bet it's more a matter of chain guns firing 6-shot bursts and suppressive fire... when modern armored vehicles actually try to shoot something do they miss all that often?

inquiring minds and all that... and if my questions betray the Stygian depths of my ignorance, let me know what I should be asking!


Thanks,
-E.

What tank and munitions are you talkng about and how much training does the crew have?

Are you talking direct or indirect far?

US tankers today can hit things far more effectively than their predecessors in WWII.  With self guiding munitions even a moving target may be easily hit.

Is anyone shooting back?  Rounds expended in combat numbers are usually averages over a fair amount of time and under situations where you are being shot at.

Quote from: XantherWhat tank and munitions are you talkng about and how much training does the crew have?

Are you talking direct or indirect far?

US tankers today can hit things far more effectively than their predecessors in WWII.  With self guiding munitions even a moving target may be easily hit.

Good questions. For the sake of discussion:

Vehicle Type: Let's say a modern NATO main battle tank or IFV -- something that has a stabilized gun, a reasonable (but maybe not top-of-the-line Fire Control System). I'm thinking about main tank gun or something like the 25mm chain gun on an infantry fighting vehicle (like a Bradley).

I assume that the chain gun, firing bursts of rounds would have a generally (significanlty) better chance of hitting than a tank gun firing a single, awesome shell

Munitions: AP depleted uranium rounds. Would HEAT make a significant difference? No self-guiding or wire-guided munitions at this point.

For my own understanding: what is "self guided?" I'm familiar with wire-guided missiles or things like hellfires that are laser-guided. I guess bombs dropped from airplanes can 'self guide' using GPS (JDAMs?) but that's not what I'm thinking about at this point.

Training: Let's assume a national army that trains regularly and fights occasionally. Let's also assume that these guys have seen some action (so it's not at the beginning of a war after a long atrophy of peacetime non-realistic training)

Fire Type: Direct fire; tank or infantry fighting vehicle points its main gun at the target, elevates for range, and fires.

Quote from: XantherIs anyone shooting back?  Rounds expended in combat numbers are usually averages over a fair amount of time and under situations where you are being shot at.

As I said before, I suspect the statistical averages don't help so much due to the vast variance in situations.

I'm looking at an RPG situation where the an NPC in a tank is "rolling to hit" a bunch of PC's in a dune buggy or something -- or maybe PC's in another tank...

So I'm looking at the individual act of firing.

I'm not aware of any game rules that assess a negative to-hit modifier for suppressive fire -- but maybe they should?

For the simple case, let's say no one's shooting back.

Does that help clarify?

Cheers,
-E.

HEAT would make a difference if it has a lower muzzle velocity and greater drag (which it generally does). Lower muzzle velocity means a less flat trajectory so there's a greater need to get the range exactly right; it also gives wind more time to affect the trajectory, and for a moving target, it requires a more difficult calculation of the target's future position.

I believe you are correct about the chance of hitting an immobile target in the open. In training exercises and competitions M1 tanks typically hit nearly every target even when the firer is moving.

Cover is another matter. It makes you harder to hit by making you harder to see; it can also physically shield you from fire, as when a vehicle is fully or partially behind a wall or a hill. So naturally if evasive movement takes you behind cover, this will be a factor.

Movement in the open in a straight line shouldn't be much of a problem for a modern FCS using a laser rangefinder. What could be a problem is moving erratically, "zig-zagging" and changing speed; this certainly created a problem for 20th-century battleships since it made it impossible to predict the target's position very far into the future, and shells could take a while to reach their destination at normal battle ranges. But tanks are operating at shorter ranges with higher muzzle velocities, even if their targets are probably faster and more maneuverable than a naval vessel. This is probably why I've seen board wargames that give a penalty for firing at a ship which has declared "evasive maneuvers" (greater than just firing at a moving vessel) but I've never seen anything similar for armor games.

You should post this question at rpg.net, old mod Cessna was a tanker in the USMC.

Quote from: -E.I'm not aware of any game rules that assess a negative to-hit modifier for suppressive fire -- but maybe they should?

From FTL Now:

"Full Automatic (Suppressive) Fire
Full automatic fire is generally used to pin down the
enemy in heavy cover, giving them substantial penalties
in firing. It is primarily a defensive option, but if the fire
happens to hit an unprotected human, the results are
generally lethal...

A successful suppressive fire pins down the opponent so
he can't move without risking being hit. A Quality of
Success roll for the suppression can be directly applied
to the opponent as a negative modifier on his Chance of
Success. Half of the Quality of success is the penalty for
full automatic fire, one quarter the Quality of Success
should be used for volley fire.

For example, a machinegun is being used to suppress
fire from three enemies using rifles. The suppression is
successful, and the machinegunner makes a Quality of
Success roll of 45. The three enemies have a negative
modifier of 23 on their attempts to hit this turn."

All StarCluster System games have variations on this rule.

-clash

It depends on the equipment and training.  Nato tanks/crews can hit moving targets while they are moving most of the time.  Many countries treat their enlisteds like crap so they have very little ability.  Such crews in generation old tanks are no better than WWII tanks - can't shoot with any accuracy while moving, will require a few shots to find the range and correct.  Slightly older tanks are also going to have difficulty with smoke/darkness.

Thanks for the replies, folks -- they've helped me focus on what I'm really trying to think through:

1) I think most games give gunners an unrealistically high  (75%+) chance to hit under "average" RPG conditions (where average = minimal cover / concealment, short or medium ranges, good visibility, trained crews, working equipment, targets moving at 20mph - 35mph, stabilized guns and modern FCS)

I'm not *sure* that my estimates are correct (I'm looking at GURPS modifiers, but maybe I'm forgetting something or using bad assumptions).

And I'm not sure that 75%+ is actually wrong -- maybe for the conditions I've outlined, that's a under-assessment...

I'm trying to figure out what modifiers *should* be accounted for that generally aren't -- or, maybe in modern combat a 75% - 85% chance of hitting under those conditions is correct.

2) For game / fictional purposes, I would *like* driving skill (and vehicle agility) to be a viable defense... I want elite PC's driving agile little dune buggies to be able to evade tank fire.

But I'd like to know if that's a total pipe dream or not before I use or develop house rules for that sort of thing.

Ideally vehicle agility rules would also account for large, slow vehicles (trucks) being easy to track and hit and small, fast vehicles or super-agile /fast vehicles (helicopters, A-10's) being hard to hit.

GURPS gives me speed / distance modifiers which I think work for jet fighters, but my impression of helicopters is that they're not as easy to hit as the rules I'm familiar with gives them.

So I guess the bottom line question is:

1) What would a good baseline modifier for what I'm considering average conditions be? If we consider somewhat skilled (but not elite) troops to have a 12- heavy weapons skill (on a GURPS / Hero 3d6 curve) that suggests an unmodified 60% chance of hitting.

If, in reality, it's more like 30% then something is more realistic (or even lower) I'd like to understand what factors are in play (is range a bigger deal in reality? Is weapon accuracy much worse than the games say it is, etc.)

2) What would be a reasonable negative modifier for evasive driving? What would be a maximum, but realistic negative modifier? Or is "evasive driving" really pure hollywood?

Cheers,
-E.

I was a tanker for 5 years, but was never a data-nerd so damned if i can respond to some of the questions, but:

Yes, hitting an immobile target with todays computer-enhanced targeting systems is about 100%.  The computer takes into account air temp, wind, etc. and unless the gunner is incompetent, it's not a big deal.

Moving targets:  lead them.  A "good driver, moving evasively" had better pray for an inept gunner, or dumb luck.

Main gun rounds rarely miss...the misses you may have read about are probably the small arms firing in concert with the main gun. I was on the M1A2 prior to the new SEP system integration, so i'm not sure how that impacts performance.

-E,

As most of the replies to the thread suggest, 75% is if anything low for the chance of hitting an observed target, at least with NATO-quality FCS. Switch to stereoscopic rangefinders, or even rangefinder by observing the size of the target silhouette in the reticles, and no fire control computer, and you could be talking much lower.

But back to top of the line. The key thing here IMO is the word observed. What proving ground tests and gunnery competitions don't account for (unless I'm mistaken; kregmosier can correct me) is that you still have to see and react to the presence & location of a target before you can shoot it. And this is what makes To-Hit chances nearly incalculable at first pass. Consider: your dune-buggy is behind a hill; 1000 m away is a Leopard II. Your plan is to break out from behind the hill, traverse some amount of open terrain, and escape behind a dense woods. Is the commander of the tank is aware of your initial location? Does he know which way you're going to come out from behind the hill? How much open space is there--meaning how long does the gunner have to acquire you--get your location and velocity? Are there other factors (such the need to watch out for other possible targets) that could slow down the tank crew's reaction time? These are all going to have an effect on the chance of being hit. From what I've read about wargame design, what you ultimately end up doing is you try to locate the factors you believe are important, you assign numerical values to them, and then you playtest to see if the relative emphasis yields plausible results in play.

Regarding your #2, while the idea of zigzagging alone being effective I think has been discarded, you still have the effect of cover both as an obstacle to penetration and as a way of foiling observation and acquisition. I don't think it's ridiculous for a dune buggy moving over undulating ground to get a defensive bonus, since it will be moving in and out of visibility, and if the driver varies his speed and direction, it will that much harder for the gunner to predict when and where the buggy will next appear, making acquisition that much more difficult.

Finally, I don't understand what you mean by "a baseline modifier for average conditions". Average (or sometimes ideal) conditions should be unmodified and then you modify from that.

Quote from: Elliot Wilen-E,
Finally, I don't understand what you mean by "a baseline modifier for average conditions". Average (or sometimes ideal) conditions should be unmodified and then you modify from that.

If the system used has a set chance of success used for everything, then a baseline modifier may be needed to pull the chance up or down if it is out of player tolerance for verisimilitude. For example, the StarCluster system gives a 45% chance at rank 1. The optics, guidance and firecontrol systems should give a cumulative +50% to bring the base chance to 95% for a non-evading, no-cover target.

-clash

Quote from: Elliot Wilen-E,

But back to top of the line. The key thing here IMO is the word observed. What proving ground tests and gunnery competitions don't account for (unless I'm mistaken; kregmosier can correct me) is that you still have to see and react to the presence & location of a target before you can shoot it.

E. - Just so.
I remember Grafenwoehr Tank table VII and VIII and that all sounds about right.
Here's some more good info:  http://findarticles.com/p/articles/mi_m0PAB/is_2_113/ai_114487497

Quote from: Elliot Wilen-E,

As most of the replies to the thread suggest, 75% is if anything low for the chance of hitting an observed target, at least with NATO-quality FCS. Switch to stereoscopic rangefinders, or even rangefinder by observing the size of the target silhouette in the reticles, and no fire control computer, and you could be talking much lower.

... snipped...

Finally, I don't understand what you mean by "a baseline modifier for average conditions". Average (or sometimes ideal) conditions should be unmodified and then you modify from that.

1) Target acquisition is clearly a big deal -- and (based on this thread) probably the best way stay alive is to avoid being seen.

2) Clearly using cover is extremely important. I was trying to simplify that out of the equation to understand how other factors might effect things, rather than ignore it. Based on what I'm reading, cover/concealment would be the only real defense a target that had been seen would have

By "average" I meant "average for an RPG combat situation" and the baseline would be (as mice said) the *unmodified* skill of the gunner.

Presumably the gunner's skill roll represents a not-ideal situation and accounts for whatever "standard" difficulties exist in imaginary engagements.

So if it's raining or if the target is unusually far away then the increased difficulty would be represented as some kind of negative modifier and the chance to hit would be "below baseline"

Conversely, if it's an ideal situation (still gunner, imobile target, no incoming fire, good FCS etc.) the game would typically represented that with bonuses to the to hit score (as in mice's example... I need to check out some of his games...)

In other words -- the ideal situation is "above" baseline.

That's because "baseline" assumes certain things -- mainly (I submit) a target that's trying not to be hit and a gunner that is unwilling to spend a long time exposed to take the shot.

But it sounds like the "baseline" for main guns actually *is* really high -- when those things fire, they don't miss.

And it also sounds like, absent cover, "moving evasively" isn't going to save anyone's life... unless it's in the movies (or maybe an RPG

Thanks,
-E.

Quote from: kregmosierI was a tanker for 5 years, but was never a data-nerd so damned if i can respond to some of the questions, but:

Yes, hitting an immobile target with todays computer-enhanced targeting systems is about 100%.  The computer takes into account air temp, wind, etc. and unless the gunner is incompetent, it's not a big deal.

Moving targets:  lead them.  A "good driver, moving evasively" had better pray for an inept gunner, or dumb luck.

Main gun rounds rarely miss...the misses you may have read about are probably the small arms firing in concert with the main gun. I was on the M1A2 prior to the new SEP system integration, so i'm not sure how that impacts performance.

Thanks -- exactly what I was wondering about. I'm disappointed that driving isn't more of a defense: another illusion punctured!

That said, I guess a real "good driver" stays behind things as much as possible... which brings me to my next question:

I've read that it takes a few seconds to bring a main gun to bear on a target. If you're shooting at something that's moving from cover to cover (or popping out from behind to cover, firing, and then ducking back) how effective is that and, specificially, in game terms would it be appropriate to give a gunner a negative modifier for having to fire more quickly than preferred?

I'm thinking of something like this:

Target available for less than 4 seconds: Huge negative to hit
Target available for 6-9 seconds: Modest negative to hit
Target available for 10+ seconds: full chance to hit (no negative)

I'm assuming that the negative accounts for an average of gun traversal time. If the target pops out directly in front of the main gun, clearly there'd be a much smaller negative modifier...

Anyway, from an rpg/rules/sort-of-kind-of-feels-like-reality perspective does this work?

Thanks,
-E.

Again I would defer to kregmosier, but that's more or less in line with what I seem to have seen in armor wargames, and for that matter other games like Avalon Hill's old Gunslinger. (The exact timescales, I'm not sure, I'm just talking the idea of taking into account the length of time that a target's visible.)

Basic idea: pick a visible target, if you shoot immediately you get a negative modifier. If you aim for a turn, you eliminate the negative. Each subsequent turn of aiming before firing gives you a bonus, up to some maximum. Target must be continuously visible during aiming.

Also I may be dreaming but I think I've seen games with longer time/turn scales, where the same effect is achieved by giving a modifier based on how many movement points (or the percentage of total MPs) the target expends while visible, before you take your shot.

But doesn't GURPS already have something like this with its snap shot and aiming rules? Combine that with a map, turn order, and regulation of movement by expending movement points, and I think you're very close.