Penetration Factor

[bjjones37]

When I used to play the Megatraveller cRPG, one of the stats of the weapons was Penetration Factor. It identified which weapons would be effective against what types of armor. In order to be able to penetrate the armor, regardless of the weapons damage potential, it had to have a Penetration Factor greater than the Rating of the Armor. Then damage could be applied. I have not noticed this mechanism employed anywhere else and was curious about it. Is it no longer considered a viable mechanism?

Example

Flack Jacket AR:3
Cloth Armor AR:5

Gauss Pistol PenF:4 Damage:4

Stats taken from Megatraveller 2 cRPG documentation.

So if you were wearing cloth armor and got shot with a Gauss pistol, you would not be injured, but if you were wearing a flack jacket, the round would penetrate and cause injury in accordance with listed damage (do not know the exact rule application).

 

[McPerth]

More or less, but not exactly...

If you hit a flak jacket, damage will be halved (50%), as penetratoin does not double the armor (low pen damage).

OTOH, a hit by 2+ over the target number will multiply the damage by 2 or more, and the automatic damage on those hits would affect even if the armor is greater than the penetration of the weapon (as would be the case for cloth).

See also pinpoint shooting...

 

[bjjones37]

I think the cRPG might have handled it a little differently. At least according to the cRPG book.

"You should compare the penetration factor of the weapon against the armor factor of an opponent to determine how effective your attack will be. If the penetration factor is greater, your assault will cause damage."

It suggests to me that this is no damage it the armor rating is greater then the penetration factor. That is how the video game seemed to play out also. I have not looked over the PnP book yet. I guess it is somewhat different. They may have scaled down the rules for the cRPG.

Thank you for the damage clarification.

 

[mike wightman]

Here is what it says in the rules:

Determining Damage: To determine the actual damage suffered
by a target, compare the weapon’s penetration at that
range to the target’s armor.
If the weapon’s penetration is at least twice the armor value,
the weapon inflicts its full damage point value. This is known
as a high penetration result.
If the weapon’s penetration is at least equal to the armor
value, then the weapon inflicts 50 percent of its damage point
value. This is sometimes referred to as a low penetration result.
If penetration is less than the armor value, the weapon inflicts
10 percent of its damage point value if the target is a
character with exposed areas of less than the full armor value.
On the other hand, if the character is fully enclosed in the armor,
the hit has no effect. Vehicles and robots always apply
such hits as structure damage. This is known as a zero penerration
result.
Marginal Success: If the task roll (including DMs) is equal
to the roll that is needed for success, marginal success (a
graze) has occurred: apply 50 percent of the normal damage
point value (drop fractions). Thus, if a weapon would inflict 50
percent damage at this range, marginal success would only
cause 25 percent damage. For example, if a weapon inflicts
3 damage points when it penetrates cloth armor at this range
on a marginal success, it would only do 1 point of damage.
Exceptional Success: If the task roll (including DMs) exceeds
the roll needed for success by:
2+ ................... apply damage points x 2 (a minimum of 1)
4+ ................... apply damage points x 4 (a minimum of 2)
8 + ................... apply damage points x 8 (a minimum of 4)
If a weapon normally causes 3 points of damage at this range
when it penetrates cloth armor, an exceptional success of 2 +
would cause the weapon to inflict 6 points of damage.
Because of the minimums, it is possible for a weapon that
ordinarily has zero penetration to inflict damage points upon
achieving exceptional success.
An easy way to remember marginal and exceptional successes’
effects on damage is: exact roll, halve it; 2+, double
it once; 4 + , double it twice; 8 + , double it three times.

 

[bjjones37]

Here is what it says in the rules:

I see. You will not find anything like this in the Megatraveller 2 cRPG game documentation. Of course I cannot really say what was coded into the actual program. Is Penetration Factor used in any other "flavor" of Traveller, or just Megatraveller?

 

[aramis]

I see. You will not find anything like this in the Megatraveller 2 cRPG game documentation. Of course I cannot really say what was coded into the actual program. Is Penetration Factor used in any other "flavor" of Traveller, or just Megatraveller?

Pen was included in Striker (CT's minis rules), and are mostly directly ported from Striker; hits were MT's addition.

While pen exists in TNE/T2K/DC, it's a different value set entirely with different meanings and mechanics.

 

[infojunky]

Pen was included in Striker (CT's minis rules), and are mostly directly ported from Striker; hits were MT's addition.

While pen exists in TNE/T2K/DC, it's a different value set entirely with different meanings and mechanics.

Well it 1st showed up in Ahzanti High Lighting then was revised for Striker.

I prefer AHL's numbers over Strikers, but Striker gives broader set of results.

 

[Timerover51]

When it comes to weapon penetration, I just look at the weapon firing and hitting, what it is hitting, and what the real world penetration would be, based on the armor penetration data that I have. If it does not penetrate, is there enough energy delivered to still cause damage? If so, then some damage is applied. If it does penetrate, say an armor-piercing round against cloth armor, then normal damage rolls. I do admit to having a lot of Real World data on armor penetration which the average player would not have. No die rolls needed for whether or not it penetrates.

Consider a .45-70 soft lead slug weighing 500 grains hitting good quality cloth armor. It may not penetrate depending on range, but it would likely deliver enough energy to break a rib or two if a chest hit. If an arm, leg, or lower torso hit in the abdomen, then normal damage as a minimum. If it looks like the bone is hit in the arm or leg, then the target is incapacitated, and no longer is part of the fight, due to the bone being shattered.

 

[McPerth]

Pen was included in Striker (CT's minis rules), and are mostly directly ported from Striker; hits were MT's addition.

While pen exists in TNE/T2K/DC, it's a different value set entirely with different meanings and mechanics.

See that in AHL (and I guess in striker too), pen included the damage capacity, and a high penetration/low damage (or vice versa) weapon did not exist.

So, a shotgun firing pellets, as has low penetration capacity, has a low factor, and that makes it less useful than it should against unarmored people too

This diferentation among penetration and damage is (IMHO) a good feature in MT combat...

 

[kilemall]

When it comes to weapon penetration, I just look at the weapon firing and hitting, what it is hitting, and what the real world penetration would be, based on the armor penetration data that I have. If it does not penetrate, is there enough energy delivered to still cause damage? If do, then some damage is applied. If it does penetrate, say an armor-piercing round against cloth armor, then normal damage rolls. I do admit to having a lot of Real World data on armor penetration which the average player would not have. No die rolls needed for whether or not it penetrates.

Consider a .45-70 soft lead slug weighing 500 grains hitting good quality cloth armor. It may not penetrate depending on range, but it would likely deliver enough energy to break a rib or two if a chest hit. If an arm, leg, or lower torso hit in the abdomen, then normal damage as a minimum. If it looks like the bone is hit in the arm or leg, then the target is incapacitated, and no longer is part of the fight, due to the bone being shattered.

Problem with an entirely deterministic resolution is it doesn't model reality either. Armor, personal or otherwise can fail, seams with weaker or no protection can be hit, or a shot may hit a deflection angle and bounce off where normally it would penetrate.

The usual US Army stats, for ammo, tank or personal armor, is penetration 50% of the time. So that's what I usually aim for in adjusting the pen effects.

https://en.wikipedia.org/wiki/Bulletproof_vest#Ballistic_testing_V50_and_V0

Note that personal body armor degrades after taking hits. Not to the level of say Ablat, but definitely happens. Guess I would go with reducing armor value by 1 for every combat the armor was struck.

Of course for tanks the functional equivalent of non-penetrating blunt force trauma is spall, which can be highly variable.

Modeling these aspects and having 'that didn't penetrate but oww it hurts' or 'small pistol usually not lethal but hit in head can kill one shot' sort of results led me to the system I use now.

 

[kilemall]

See that in AHL (and I guess in striker too), pen included the damage capacity, and a high penetration/low damage (or vice versa) weapon did not exist.

So, a shotgun firing pellets, as has low penetration capacity, has a low factor, and that makes it less useful than it should against unarmored people too

This diferentation among penetration and damage is (IMHO) a good feature in MT combat...

Hmm, probably so, even with my system the high pen weapon is going to do 2/3D worth of damage against a non-armored opponent, before adding in the body location (likely 1/2D).

A low pen high damage round would likely get the HE/blunt damage extra 1D, so that's handled. Also allows for a mace/hammer to do damage, even if it doesn't penetrate per se.

Don't see your point on Striker shotguns, they are usually at least 2-3 hits which add up to incapacitated or killed on unarmored.

Reminds me, I need to work up high tech shotgun shells-something like an AA missile/shell that detonates 1-2 meters away from a target group. Always room for scary improvement.

 

[McPerth]

Don't see your point on Striker shotguns, they are usually at least 2-3 hits which add up to incapacitated or killed on unarmored.

I didn't alk about striker, as I don't know it, but about AHL (and guessed it also affected striker, as I've been told they are quite close). In AHL, a shotgun has a pen of 3 at short range (but a +5 to hit). That means a cloth armored target will have a -3 DM (so wil lbe unhurt on a roll of 6-).

An ACR, also at short distance, has a pen of 4. That makes it better than a shotgun agains armored people (wich, being not a military expert to say the least, I guess is fine), but it also makes better than a shotgun against unarmored people, and is here where I cast some doubts, as shotguns use to be quite deadly against them.

 

[kilemall]

Shotguns get that DM fire. Just looked it up, +6 close on Striker.

The key rule is the multiple hits rule- for every + 2 over the needed to- hit, you score an extra hit.

So let's Starman McFumble, a ship crewman with no gun skill, gets handed a shotgun and told to hold the hallway. The baddies round the corner and he fires.

No skill, effective range so 8+ he hits. He rolls a 7 each against both of the targets.

But because it's a shotgun, he gets an adjusted roll of 13.

Well that's not only a hit, but 5 over the needed roll of 8. So he got 1 base hit plus 2 additional hits- three chances to get an outright kill, and the simplified hits add up to at least an incapacitation even if all of them came up minor wound.

In my system, baseline 7 rolls for hit location and penetration, pellets get +1 but that's still not extra damage, so figure 2D per hit for thoracic damage, for 6D total.

Shotguns DOUBLE that +6 on autofire, so +12- virtually no chance to miss, and a good chance of 1+5 hits.

Shotgun bullets on autofire are in a way scarier, less chance to autohit but each hit is like a rifle.

Frankly, I don't see why people cry about gauss rifles with these bad boys in play.

I'd have to go back and look at AHL to see if this is in there or not.

EDIT- it's not, just a real high chance of hitting, but for unarmored it's sort of built into that higher pen value.

 

[kilemall]

Holy yak, rereading these things, always a surprise.

I always read that multiple hit rule to be specific to autofire, shotguns, multiple shot situations.

But there is no such thing. It's basically saying you could luck out on your hit and do multiple hits even on a single shot, and a veteran is adding +2 to that to hit meaning rolling an 8 for them is ALWAYS two hits.

I would interpret this to mean the vet is advantaged to the point of being able to take the better shot presented and do more damage rather then literally magic bullet two hits with a single shot.

I've got this subsumed in a higher damage hit location skill advantage, but I think I would continue to interpret that per shot rather then rolling multiples on single shots.

 

[Timerover51]

I didn't alk about striker, as I don't know it, but about AHL (and guessed it also affected striker, as I've been told they are quite close). In AHL, a shotgun has a pen of 3 at short range (but a +5 to hit). That means a cloth armored target will have a -3 DM (so wil lbe unhurt on a roll of 6-).

An ACR, also at short distance, has a pen of 4. That makes it better than a shotgun agains armored people (wich, being not a military expert to say the least, I guess is fine), but it also makes better than a shotgun against unarmored people, and is here where I cast some doubts, as shotguns use to be quite deadly against them.

The spread of a pattern of buckshot from a shotgun is about 1 inch per yard of range. At 10 yards, that would put the entire pattern into an armored person's torso, along with pretty high penetration. An ACR would have one projectile, the buckshot load for a shotgun will have between 9 and 15 projectiles, assuming a 12 gauge gun. That is a lot more effective hits than the ACR, which should make the shotgun a lot more deadly at close range.

For a shotgun at close range, it if hits, I would roll a D6 for the number of damage die rolls. That would make the shotgun sufficiently deadly compared to other weapons.

 

[McPerth]

The spread of a pattern of buckshot from a shotgun is about 1 inch per yard of range. At 10 yards, that would put the entire pattern into an armored person's torso, along with pretty high penetration. An ACR would have one projectile, the buckshot load for a shotgun will have between 9 and 15 projectiles, assuming a 12 gauge gun. That is a lot more effective hits than the ACR, which should make the shotgun a lot more deadly at close range.

That would be true if the target is armored with cloth, but most cloth armored people in AHL are in fact in vacc suit (armor is equivalent, and remember AHL happens inside a ship), and I guess in this case the ACR, having more penetration capacity, would be more deadly than a shotgun...

Same reasoning wil lapply if armor is CES , or any other full body armor (Combat Armor, Battledress, etc).

The fact is that makes it less lethal against a unarmored person, and that's what is hard to swallow for me...

 

[aramis]

Well it 1st showed up in Ahzanti High Lighting then was revised for Striker.

I prefer AHL's numbers over Strikers, but Striker gives broader set of results.

Striker's numbers are the ones DGP used.

 

[infojunky]

Striker's numbers are the ones DGP used.

So? The specific numbers are just that. I was talking about the chain of ideas. Heck one sees the evolution of the numbers towards striker if one reads the AHL based scenarios in jTas...

By skipping AHL one skips a evolutionary step in rules development.

 

[aramis]

By skipping AHL one skips a evolutionary step in rules development.

Point taken.

 

[Timerover51]

I was going through my files and came across my copy of FM 90-10-1, INFANTRYMAN'S GUIDE TO COMBAT IN BUILT-UP AREAS, May of 1993. It has a very nice appendix of terminal ballistics in an urban environment of various weapons, ranging from the M16 to tank gunfire and aerial weaponry. In the segment on the M16, the following comment appears. It does make for some interesting thoughts on bullet penetration.

(1) For the 5.56-mm round, maximum penetration occurs at 200 meters. At ranges less then 25 meters, penetration is greatly reduced. At 10 meters,penetration by the M16 round is poor due to the tremendous stress placed on this high-speed round, which causes it to yaw upon striking a target. Stress causes the projectile to break up, and the resulting fragments are often too small to penetrate

(2) Even with reduced penetration at short ranges, interior walls made of thin wood paneling, sheetrock, or plaster are no protection against 5.56-mm rounds. Common office furniture such as desks and chairs cannot stop these rounds, but a layer of books 18 to 24 inches thick can.

(3) Wooden frame buildings and single cinder block walls offer little protection from 5.56-mm rounds. When clearing such structures, soldiers must ensure that friendly casualties do not result from rounds passing through walls, floors, or ceilings.

Then is then a considerable discussion of what materials will stop the standard M16 round that you would encounter in urban combat. Quite a lot of very good information applicable to both Traveller and especially Twilight 2000 in that manual. I will have to get out the World War 2 equivalent that I have somewhere. I did find the comments on the M16 round quite interesting.