View Full Version : M1A2 pk stats

12 Aug 03, 19:23
I'm revising the Death Valley Attack Scenario. I want to replace all AT-5 teams with the new AT-7 team.

The AT-7 has a 460mm penetration HEAT warhead with a range min/max: 40/1000m. The M1A2 Abrams has a declassified protection of turrent: 1310-1620 Glacis: 510-1050, lower front hull: 800-970. Even if I took the lower end of this number, it would mean the M1A2 should be invulnerable to frontal attack by the AT-7 and nearly invulnerable to attacks on the sides and rear. The numbers I wanted to use are as follow:

Top: 15
Front: 0
Right: 10
Left: 10
Rear: 10 or maybe 15

Turret can be invulnerable

Anyone have a problem with these numbers?

Invulnerability should not break the scenario. There are plenty of AT-5s on the battlefield assigned to the BRDM-2s. They are more than capable of blowing your force to the moon. I don't plan to change the stats of any other vehicle except the M1 Abrams series. The AT-7 should destroy anything else on the battlefield.

Which brings me to another question. How could a M2 bradley survive a hit from an AT-5, when it has trouble surviving an RPG-7 in real life? I was thinking about changing those numbers from around 70 to at least 90 if not 100. I might be wrong though.

14 Aug 03, 17:06
There is no such thing as "invulnerable" when it comes to tanks.

It is quite possible for a smaller weapon to penetrate and kill even the front side of the formidable M1A2. All tanks have weak spots. The hatches are notable, along with the gunner's sight, the gun mounts, and the turret ring. Keep in mind that it is not necessary to blow up the whole vehicle to "kill" it; just to inject enough spall inside to scramble the crew. "Killed" vehicles are very often made ready for service again without much trouble; the same often can't be said for the unfortunate crewmembers.

Similarly, it is very possible for a powerful weapon to score a bad hit. High angle of impact or a grazing hit; a dud warhead; or even full penetration that simply fails to encounter anything important on its path through the vehicle. The thicker and/or more sloped the armor is, the more likely any given hit will be "bad". The M2 is pretty heavily armored for an IFV; I can believe the stats for the front. Compare them with the M113, for example, which is both boxier and thinner.

The sides and rear stats for all vehicles and especially tanks I find less believable. I find it difficult to agree that a TOW2A has only a 35% of killing a T80 from the rear, and even less so that it is only 10% greater than the frontal chance. Personally, I would increase the side, top, and rear pKs for all ATGMs and main guns >90mm, with a maximum of 95%. Against top-attack weapons like Javelin and TOW2B, I would make all aspects the same as the top aspect. For smaller HEAT weapons like RPGs in the 60mm-90mm range I'd add 25%. I wouldn't increase it at all for small caliber AP and really small HEAT < 60mm. Again, this is against all aspects *except* the front. I wouldn't change most frontal values.

On the other end, I would give any weapon specifically dedicated to the antitank role a minimum 5% chance of killing any vehicle from any angle. This doesn't include "expedient" weapons like 40mm grenades and .50 cal, which can be down to zero.

There's another issue. Due to the convergence of ROF and pK, it is quite possible for certain rather ineffective weapons to be just as if not more effective than other, more suitable weapons. A gross example is the M2 chain gun, which is set to 10% on the sides. Given that the 25mm can fire roughly seven times faster than the TOW, it is significantly *more* effective than the TOW in kills/minute against the sides of a T80.

Perhaps that 10% was a typo. A less egregious but still surprising result that is probably not an obvious error is .50cal. When you factor in reload times, it is approximately as effective in kills/min as TOW against the sides and rear of T80 tanks. I would suggest this is more due to the unrealistically low performance of TOW than unrealistically high performance of .50 cal.

There is also a tertiary issue: do you want certain weapons shooting at certain targets. Unfortunately, the only way to solidly turn off direct fire, to my knowledge, is to set the pK to zero. The most obvious example here is the ATGM vs. infantry issue.

Personal opinion aside, the AT-7 is comparable to the Dragon. So, you can base your numbers on that weapon's performance against similar vehicles. Whether you use the orthodox ATF numbers as your base or the "enhanced" numbers I suggest is up to you.

--- Kevin

Pat Proctor
14 Aug 03, 18:23

Your analysis of the effectiveness of small arms vs. heavy weapons against different weapon systems ignores the impact of pH on the equation. Remember that, before the pK is ever applied, the weapon system has to hit the target.

Yes, the .50 cal, when you fire max rate of fire and multiply shots X pH yields a higher number in 45 seconds than the TOW missile. But the TOW missile has 11 times the optical magnification and almost four times the range. So, at 1000 meters, the max engagement range of the .50 cal, the TOW has a 44 X better chance to hit (this is a huge simplification of the actual pH algorithm, but it conveys the point).

The 25mm numbers are not quite as radically divergent, but the TOW is probably still at least twice as likely to hit as the the 25mm.

14 Aug 03, 19:16
But the TOW missile has 11 times the optical magnification and almost four times the range. So, at 1000 meters, the max engagement range of the .50 cal, the TOW has a 44 X better chance to hit (this is a huge simplification of the actual pH algorithm, but it conveys the point).

I think your analysis is also in its turn missing the point.

What you are saying, in effect, is that the only real difference in killing power between a TOW system and a .50 cal is the sight system. Ergo, in game terms, we should be able to "upgrade" the .50 cal to a tank-killing system with performance comparable to the TOW (at least to the sides and rear within 1000m) by improving the sights. Put a 44x telescopic sight on it, and there you go.

By using the 44x number, you are also saying that the maximum possible chance for a .50 cal burst to hit a tank is around 2%. I frankly dispute whether is is all that difficult to hit a tank-sized target at 1000m with .50 cal, even over iron sights. With decent visibility and competent tracer sensing, it is in fact quite easy. *Of course* it will not be very effective, even against lighter armor; but not because you're not hitting the target.

There is also the question of accuracy profile. I suspect that the pH system is based on a ballistic curve, while ATGMs typically have a linear curve from minimum to maximum. So, again, ATGMs in general will underperform at max range.

I'm not all up in arms about these issues like I am about certain other issues. I will point out, though, that the surprising toughness of tanks to the side and rear (to certain weapons, that is, while showing curious vulnerability to others) is *yet another* factor conspiring to reduce the effectiveness of infantry, which count among their strengths the capability to sneak around to the sides and rear, as well as minimizing the reward for good tactics in general that set shooters up for side shots.

In the end, I will simply say that I think there should be a bright line between pH and pK, and issues in one shouldn't be compensated for by manipulating the other. Unfortunately, the database as is leaves the end user with little choice, since pK is all that is available.

--- Kevin

15 Aug 03, 13:07
Having had a chance to think it over a bit, I think I failed to communicate my real point in the last post, having gotten bogged down in technical minutiae.

My discussion of .50 cal vs. tanks brings me right back to earlier arguments. Most of the time, troops aren’t going to shoot .50 cal at tanks, especially in disciplined, modern forces with much better AT weapons at their disposal. Even if they do, it is highly unlikely to result in a “killed” tank --- we’re talking millipercent chances here.

Yes, I know the arguments. They could do it, yes. It might have some effect, yes. Anything is possible. But, I think things should be judged less on what is possible and more on what is probable.

It would make sense to consider desperate, last-ditch acts of defiance if the game modeled desperation. But it doesn’t.

It would make sense to consider low-odds fire by unsuitable weapons in the hopes of getting some sort of disabling damage like a broken track if the game modeled systems damage. But it doesn’t.

Given the limitations of the engine, I think the emphasis should be placed on accurately modeling what usually happens, and not getting overly concerned with what might happen in unusual circumstances.

99% of the time, nobody is going to try to kill a tank with .50 cal. 99% of the time, nobody is going to waste an ATGM shooting it at infantry. Admittedly, 1% of the time such unusual actions might make sense. Unfortunately, the game doesn’t have a means to enable a 99%/1% split. The choice is between “always” and “never”.

Right now, the decision seems to be that it is preferable to model the 1% situation, and therefore certain weapons are always fired at unsuitable targets. The game is therefore now unrealistic in 99% of those situations.

I think it would be better if the game was set to never fire at unsuitable targets, and therefore it would only be unrealistic 1% of the time.

--- Kevin

15 Aug 03, 17:45
I've thought about the pk figures so much I see it in my dreams!

For the AT-7, I took kbluck's advice and used the M47 figures to determine figures. (Althugh I don't know if it ever be used in Death Valley: Attack. Tried to import today and it just crashed the builder!?)

Again, I think what the enemy fires upon should be determined by the scenario editor. During heavy fighting in Iraq, one Abrams was lost when an Iraqi shot and killed either the commander or the driver, causing the tank to roll off a bridge. The crew was trapped and drowned. One could argue small arms fire killed the tank. In another incident, an M1A1 was disabled when an Iraqi hit it with an RPG-7 in the rear.

So there is a valid argument for having anything shoot at anything at anytime. The scenario builder should be able to decide who fires at what based on his or her vision of the battle. If you are fighting a well-disciplined Army, one could expect them to try and use combat power appropriately. On the otherhand, if you are fighting a bunch of determined, but poorly trained soldiers, anything goes.

As for the pH, I don't really understand it, and thus can't really talk about it. I'm having a *itch of a time with the stuff I have now. I want accuracy, however, I wonder just how realistic should be.

I'm going to try and produce another scenario now. I'll let kbluck beat me up side the head with equations when it comes out. :D :D

Pat Proctor
16 Aug 03, 13:56
Let me know if you continue to have issues trying to import the Database. I will debug.