How effective is body-armor IRL?

[Golan2072]

Now that I've decided in favor of damage-absorbing armor rules, I have to set the absorbance level of each armor type and the penetration (that is, the amount of absorbance it ignores) of each weapon type.Towards that end, I'm looking for input in order to keep this system realistic in feel (even though it is a compromise with realism for the sake of gameplay ease). Specifically, I want to know the following:

1) How efficient is a bullet-proof vest (Flak in CT terms) in stopping pistol/SMG rounds? Rifle rounds?

2) How efficient is a heavy-duty kevlar vest (Cloth in CT terms) in stopping pistol/SMG rounds? Rifle rounds?

3) How effecive was archaic or semi-archaic chainmail in stopping modern projectiles? Primitive projectiles? Melee weapons?

4) How effective are modern combat armors (light kevlar, heavy kevlar, ceramic) against melee weapons?

 

[Ptah]

Originally posted by Employee 2-4601:
Now that I've decided in favor of damage-absorbing armor rules, I have to set the absorbance level of each armor type and the penetration (that is, the amount of absorbance it ignores) of each weapon type.Towards that end, I'm looking for input in order to keep this system realistic in feel (even though it is a compromise with realism for the sake of gameplay ease). Specifically, I want to know the following:

1) How efficient is a bullet-proof vest (Flak in CT terms) in stopping pistol/SMG rounds? Rifle rounds?

2) How efficient is a heavy-duty kevlar vest (Cloth in CT terms) in stopping pistol/SMG rounds? Rifle rounds?

3) How effecive was archaic or semi-archaic chainmail in stopping modern projectiles? Primitive projectiles? Melee weapons?

4) How effective are modern combat armors (light kevlar, heavy kevlar, ceramic) against melee weapons?

I'll stick with actual examples.
On 1) & 2) a friend of my who is a police officer told me of a shootout he was in about a year ago. His collegue was hit in the vest with a could of 45 ACP rounds from about 20 feet or less. He lived but the "wound" produced a swelling/lump abot the size of an orange and the guy was white as a sheet.

On 3) I was saw an excellent demonstration on the effectiveness of gunpowder. A candle (yes soft wax candle) was fired through a 1 inch thick oak board from a black powder rifle from about 10 feet. Smokeless powder was used as this was inside and I'm sure the load was faily low for safeties sake. Of course this isthe same demostration where we saw the combustability of liquid oxygen.

 

[Anthony]

Originally posted by Employee 2-4601:
Specifically, I want to know the following:

1) How efficient is a bullet-proof vest (Flak in CT terms) in stopping pistol/SMG rounds? Rifle rounds?

Depends on the rounds in question. A level IIIa vest always stops pistol/SMG rounds that hit the vest, and never stops rifle rounds. A lightweight flak vest (essentially not used today) will stop a light pistol round and not much else.

[qb]
2) How efficient is a heavy-duty kevlar vest (Cloth in CT terms) in stopping pistol/SMG rounds? Rifle rounds?

See the above.

3) How effecive was archaic or semi-archaic chainmail in stopping modern projectiles? Primitive projectiles? Melee weapons?

Totally ineffective vs bullets; it tends to worsen wounds because fragments of mail get driven into the body along with the bullet. Quite effective against primitive projectiles and melee weapons.

4) How effective are modern combat armors (light kevlar, heavy kevlar, ceramic) against melee weapons?

For kevlar, depends if it's designed to be stab-proof; many suits are not, as it adds extra weight. Properly designed, kevlar is very resistant to cutting and stabbing weapons. Against crushing weapons, such as a mace, it's basically padding. Ceramic or metal inserts will stop any melee weapon ever made, though the impact may be unpleasant and the coverage is quite limited.
Depends if they're designed to be knife-resistant. Insert plates (ceramic or metal) will stop

 

[Supplement Four]

I use the Armor Values for Striker (which were copied into MT later). So, each armor type has a base AV. The base AV of an armor is subtracted from the damage roll (reducing damage to the character).

But, also also use another DM to the damage roll in my game, based on weapon penetration.

I use the standard CT armor DM table as a penetration table. These DMs do not modify the attack throw, as in vanilla CT. Instead, they modify the weapon's damage vs. specific CT armor types.

Here's an example:








If you pick up an autopistol in my game, the weapon will do a base of 3D damage, modified by the two DMs I mention above (base AV, and Weapon Penetration).

So, the weapon will do different damage based on what it hits...

</font><blockquote>code:</font><hr /><pre style="font-size:x-small; font-family: monospace;">3D +1 vs. No Armor
3D +1 vs. Jack
3D -3 vs. Mesh
3D -8 vs. Cloth
3D +1 vs. Reflec
3D -2 vs. Ablat
3D -13 vs. Combat
3D -15 vs. Battle Dress</pre>[/QUOTE]What I like about this system is that it already uses CT numbers. You don't have to make things up. AVs are available in Striker (or MegaTraveller), and the weapon penetration DMs are the same as shown on the "Defender's Armor" table in Book 1. Just add the armor's AV to the penetration value, and you've got your modifier to damage.

For example, Cloth Armor is AV5. An AutoPistol vs. Cloth, on the table, shows "-3". Sum those together, and you get a modifier of -8. The AutoPistol will do 3D -8 damage when it hits a part of the target's body protected by Cloth Armor.

Simple as that.

 

[robject]

That's a very good way to update the CT combat system, S4. It does require two rolls per attack, right?

I wonder if the attack roll can be combined with those DMs to produce a one-roll action... I guess not.


Employee, in case you don't know:

T4 used armor to absorb dice of damage, with all personal weapons essentially having pen 1, resulting in very fast combat with most firearms. Nastier weapons would bring pen considerations into the game. I suspect it might be hard to reconcile with Striker armor levels.

T4 assigned personal armor values in the range of 1 to 10 or so, with TL12 battledress coming in around 6 or 7. This meant battledress would absorb the first 6 or 7 dice of damage.

Furthermore, armor was divided into two types: flex and rigid. Flex converted dice of damage into single points of damage, while rigid armor absorbed the damage completely. I believe each also had certain other properties -- for example, flex was better against blade weapons. I can't remember for sure, though.

 

[Supplement Four]

Originally posted by robject:
That's a very good way to update the CT combat system, S4. It does require two rolls per attack, right?

It's an attack roll and a separate damage roll (if a hit is obtained), just like in vanilla CT and most other rpgs.

Two rolls: one for attack and one for damage.





The attack roll (gun combat) is modified by Skill, weapon's DEX DM, and Range to target.

The damage roll is modified by what you see above: base armor modifier and weapon penetration.

I wonder if the attack roll can be combined with those DMs to produce a one-roll action... I guess not.

Are you looking for a single roll for both attack and damage?

I actually had a Traveller system for that about a year ago, but I dropped it in favor of UGM.

 

[robject]

Nope, I just wanted to make sure there wasn't a roll to hit, then a roll to pen, then a roll to damage. Sorry about that, my mind muddles itself up.

 

[Supplement Four]

Naw, it's just an attack roll and then a damage roll if the attack is successful.

The weapon penetration comes in the form of a modifier to the damage roll.

Take the AutoPistol vs. Cloth armor example above. The AutoPistol does a base 3D damage. Cloth armor is AV 5. That's 3D -5.

But, we haven't added in weapon penetration, which we get from the CT armor chart. AutoPistol vs. Cloth is "-3", so we add that into our roll as well (the second modifier to damage).

What we end up with is a single damage roll: 3D -8.




And, what does "3D -8" damage mean? It means that, if we roll 3D, and end up with a total of 8 or less, then the weapon will not penetrate the armor.

If our 3D roll is 9 or higher, then the weapon will penetrate to the tune of the difference.


Example 1. AutoPistol vs. Cloth (3D -8)

Roll 3D: 2, 4, 1

The Cloth armor absorbed all this damage (7 points), and the pistol did not penetrate the armor.





Example 2: AutoPistol vs. Cloth (3D -8)

Roll 3D: 6, 5, 4

The AutoPistol DID penetrate the cloth armor, to the tune of 7 damage points.

The AutoPistol blasted a hole in the Cloth, and the target took 7 points of damage from the shot (the Cloth armor absorbing 8 points from the shot).




Penetration, under my set of CT tweaks, works like that.

 

[Golan2072]

Originally posted by robject:
Employee, in case you don't know:

T4 used armor to absorb dice of damage, with all personal weapons essentially having pen 1, resulting in very fast combat with most firearms.

I know very well about the T4 armor system, which is the inspiration for my armor house-rules. However, I'll probably make rifles prenetrate armor better than pistols for abit of added realism, and I'm not sure if I'll use the Hard/Soft division. My reason for posting the questions in my above post is to get a feel for armor and penetration values to use in my variant system.

 

[whartung]

I admit to not being up on the various armor levels (I, II, III, IIIa).

But, while a typical modern vest stops pistol bullets and not rifle bullets, with the ceramic inserts, it WILL stop a rifle bullet, at least the AK-47 et al in use today.

However, the ceramic piece (trauma plate) adds weight and is only in a select section of the vest.

For probably more than you want to know about the subject, you can go to: http://www.theboxotruth.com/

This guys shoots all manner of things at all manner of things (including the modern vests and a (if I recall) a Vietnam era vest). Interesting results.

Also, note that pistol and rifle fire is a different problem than fragments and "flak".

 

[Supplement Four]

Originally posted by whartung:
I admit to not being up on the various armor levels (I, II, III, IIIa).

Palladium put out a superb modern weapons & equipment book some years back. IIRC, it discussed all levels of real life armor and such. I've got that book in a box somewhere around here. I outta dig it out.

 

[Uncle Bob]

http://www.nlectc.org/pdffiles/0101.04RevA.pdf

2.1 Type I (22 LR; 380 ACP)
This armor protects against .22 caliber Long Rifle Lead Round Nose (LR LRN) bullets, with nominal masses of 2.6 g (40 gr) impacting at a minimum velocity of 320 m/s (1050 ft/s) or less, and 380 ACP Full Metal Jacketed Round Nose (FMJ RN) bullets, with nominal masses of
6.2 g (95 gr) impacting at a minimum velocity of 312 m/s (1025 ft/s) or less.
2.2 Type IIA (9 mm; 40 S&W)
This armor protects against 9 mm Full Metal Jacketed Round Nose (FMJ RN) bullets, with nominal masses of 8.0 g (124 gr) impacting at a minimum velocity of 332 m/s (1090 ft/s) or less, and 40 S&W caliber Full Metal Jacketed (FMJ) bullets, with nominal masses of 11.7 g
(180 gr) impacting at a minimum velocity of 312 m/s (1025 ft/s) or less. It also provides protection against the threats mentioned in section 2.1.
2.3 Type II (9 mm; 357 Magnum)
This armor protects against 9 mm Full Metal Jacketed Round Nose (FMJ RN) bullets, with nominal masses of 8.0 g (124 gr) impacting at a minimum velocity of 358 m/s (1175 ft/s) or less, and 357 Magnum Jacketed Soft Point (JSP) bullets, with nominal masses of 10.2 g (158 gr) impacting at a minimum velocity of 427 m/s (1400 ft/s) or less. It also provides protection against the threats mentioned in sections 2.1 and 2.2.
2.4 Type IIIA (High Velocity 9 mm; 44 Magnum)
This armor protects against 9 mm Full Metal Jacketed Round Nose (FMJ RN) bullets, with nominal masses of 8.0 g (124 gr) impacting at a minimum velocity of 427 m/s (1400 ft/s) or less, and 44 Magnum Semi Jacketed Hollow Point (SJHP) bullets, with nominal masses of 15.6 g
(240 gr) impacting at a minimum velocity of 427 m/s (1400 ft/s) or less. It also provides protection against most handgun threats, as well as the threats mentioned in sections 2.1, 2.2, and 2.3.
2.5 Type III (Rifles)
This armor protects against 7.62 mm Full Metal Jacketed (FMJ) bullets (U.S. Military designation M80), with nominal masses of 9.6 g (148 gr) impacting at a minimum velocity of
838 m/s (2750 ft/s) or less. It also provides protection against the threats mentioned in sections 2.1, 2.2, 2.3, and 2.4.
2
2.6 Type IV (Armor Piercing Rifle)
This armor protects against .30 caliber armor piercing (AP) bullets (U.S. Military designation M2 AP), with nominal masses of 10.8 g (166 gr) impacting at a minimum velocity of 869 m/s (2850 ft/s) or less. It also provides at least single hit protection against the threats mentioned in sections 2.1, 2.2, 2.3, 2.4, and 2.5.p

 

[Supplement Four]

Uncle Bob posted some RL body armor qualifcations. Here's some more RL info (some of it duplicated from Bob's post), with a little extra info.

Mixed in is some rpg rules from the Top Secret/SI game (to give you an idea of how to port it to Traveller).

Hope you find it useful, Omer.






-------------------------------------------------

1. CLASS: There are 5 classes of body armor and 3 classes of helmets, each of which refer to protection rating, weight, and concealment. Each class adds +1 point of protection to a covered hit location. The classes, referred to from now on as AC, are as follows:

AC 1 (very light, 3-5 lb.)- Pullover nylon and kevlar skinsuits, highly concealable (+20 INT to detect). No MOV penalty. Protection rating versus .22, .25, .30, .32, .38, 9mm, or any 1d6 class ammo

AC 2 (light, 5-10 lb.)- Woven kevlar vest, concealable (+10 INT to detect). No MOV penalty. Protection rating versus .380, .40, .41, 10mm, 11mm or any 1d6+ class ammo

AC 3 (medium, 10-15 lb.)- Padded kevlar vest or jacket, somewhat concealable (no INT mod to detect). +5 MOV penalty. Protection rating versus .45, .357, 4.6mm, 5.45mm, 5.56mm, 7.62mm, 7.65mm, or any 1d8 class ammo

AC 4 (heavy, 15-25 lb.)- Reinforced kevlar vest or jacket with ceramic plating or molded modular ceramic vest, poor concealment (-20 INT to detect, causes bulges and disproportionate areas). +10 MOV penalty. Protection rating versus .44, .300, .338, 20 GA slugs, or any 1d8+ class ammo

AC 5 (very heavy, 25-50lb)- Reinforced kevlar vest or jacket with steel plating, or padded flack jackets and bomb suits, no concealment (no matter how hard the PC tries to hide it, someone will notice something doesn't look right). +15 MOV penalty. Protection rating versus .50, 12.7mm, 12GA slugs, or any 1d10 class ammo.

HELMETS: Made of reinforced plastic, ceramics, or steel, they range from AC 1-3 depending on type. Obviously, they are unconcealable.

2. DAMAGE: Where armor protects a body location, the dmg rolled must exceed the AC for the round to penetrate, and the dmg result is only the difference between the AC and the roll. Note that vests cover the front and back torso and abdomen, jackets cover the shoulders and arms, and pants cover the upper and lower legs. A shot coming from behind should only effect the hit location to the rear, and does not degrade the overall AC, only the area where the round made contact.

3. DEGREDATION: Every time a location is penetrated the AC looses 1 point to degradation. When a hit location has been penetrated the number of times = to AC, it is considered totally degraded, and offers no protection. Eventually degraded armor needs to be replaced due to warping and tears, however, modular and plated armor requires only that the damaged segment be replaced, not the whole suit.

4. AMMO CLASS: If a type of ammunition exceeds the class against which the suit was rated to protect, the round causes dmg as normal, except that it must assess dmg against the suit first before transferring to the body location. Furthermore, the round degrades armor immediately, negating all AC bonuses the next time that location is hit.

5. SPECIAL RULES:

APR: Armor piercing rounds such as steel jackets, nylon penetrators, and needle rounds treat AC as if they were a higher ammo class than the jacket was designed to protect against. In other words, the round assesses its dmg against the suit before moving onto the person, and it too permanently removes AC bonuses.

MODIFIED AMMO: Some ammo has been altered to cause special damage to a target. For example, nylon coated rounds and needle rounds are designed to cause more dmg versus armor, but suffer a -1 dmg penalty versus live targets. Parabellum rounds or hollow points are designed to cause more dmg to live targets, but suffer a -1 dmg penalty versus armor. Low velocity rounds like ball ammo suffer a -1 dmg penalty versus both. Hard ammo such as steel jackets suffers no dmg penalty versus either. Shotgun slugs are designed to penetrate armor, but buckshot rounds, while intended to cause significant damage to live targets, will generally scatter versus armor (unless fired at point blank range). Unless otherwise noted, shotgun ammo should be treated as a lower class of ammo, that penetrates armor only if the roll exceeds the AC, and like lower class ammo, assesses dmg as the difference between the AC and the roll.

EXCEPTIONS and EXCLUSIONS: .50 BMG rounds and Anti-materiel ammo like depleted uranium rounds ignore AC completely. They are either high velocity rounds that fire at such great speeds such that armor is ineffective, or they are specifically designed not to eject their payload until after passing through armor. Explosive and Incendiary ammo is subject to AC rules, but may still have consequences for area effect. Fletchette rounds are designed to be nonlethal, and therefore have no effect versus armor whatsoever, even at point blank range, where they could kill someone unprotected. Some ammo is simply so heavy that armor provides little advantage. For example, 14.5mm machine gun rounds, 20mm cannon and recoilless rifle rounds, or any ammo that is classed at 1d12 and up will generally soak up AC. Transfer the excess dmg to the person, and unless the roll was very low, there should be enough left over dmg points to kill a live target. Other weapons fit into the ammo class category but their rate of fire is so great that it nullifies the advantage of armor. For example, the 7.62mm General Electric XM214 Minigun, the 7.62mm PKT tank gun, or the .50 Browning FN M3 fires a standard round, but the weapons themselves are rated at 1d12 because they can expend 1000-1600 RPM, and can do so accurately with no pause in their Rate of Fire because of their high ammo loads. Like heavy ammo, unless the roll was very low there should be enough left over dmg points to kill a live target after the armor is chewed away.

6. REALITY: ROF and Velocity issues are already addressed in TSSI's standard rules regarding handheld weapons. Obviously, a 9mm pistol fires a heavier round than a 5.56mm assault rifle, but the ROF and Velocity output of the assault rifle exceeds a pistol, and therefore, can cause more dmg. These AC rules continue to reflect the physics of this reality rule for mounted and vehicle weapons, and hopefully help to justify why one ammo class of a higher caliber or measurement can do less damage than another ammo class of a lower caliber or measurement versus armor.

 

[mwturnage]

Originally posted by Employee 2-4601:
3) How effecive was archaic or semi-archaic chainmail in stopping modern projectiles? Primitive projectiles? Melee weapons?

4) How effective are modern combat armors (light kevlar, heavy kevlar, ceramic) against melee weapons?

My Cr .02:

Chainmail was quite effective against archaic melee weapons; there's a reason why it stayed in use for almost eighteen centuries. It would stop most slashing cuts and projectiles well, though it offered much less protection against the force of a blow (one of the reasons for the popularity of the mace). It never really fell out of use; it was just supplanted by plate armor, which allowed for greater all-around protection.

Against modern weapons, mail of good enough quality mightstop a pistol round from completely penetrating, but the victim is still going to be in for a world of hurt from the blow. A rifle round is just going to blow through it like butter.

(You didn't ask, but plate armor not only protects well against archaic melee and missile weapons, it also did fairly well against light firearms. Late plate armor was often 'proofed' by use of a pistol. A family member who is an armorer has done the same thing with a .38. I'd still rather have modern body armor ala the Interceptor , but I can see it stopping a pistol round, and at least helping some against a rifle round)

As for modern armor vs melee weapons, it was discovered early on that blades did quite well against straight kevlar and such. In fact French peacekeepers in Africa in the 80s suffered a few dozen casualties to knife attacks, and I'm sure any big city police force had the same. Now most body armor has at least one layer dedicated to stopping blades, usually involving a steel or ceramic insert. This is one of the reasons why many armors are so bulky...