7g) Combat -- Armour and Penetration

Armour and Penetration

Every attack has a Penetration (PEN) stat, and every target has a corresponding Armour Value (AV). Both of these numbers can be as low as zero or as high as a thousand.

PEN and AV values are not linear – that is to say that AV 2 is not double the thickness of material than AV 1, and a weapon with PEN 4 is much more than twice as powerful as one with a PEN 2. In the real world, the 7.62mmS round fired by the AK-47 (PEN 6) can penetrate 6mm (¼”) of steel plate – not bad for an assault rifle – while a .50 BMG heavy machine gun round (PEN 12) can penetrate 20mm (¾”) of the same material.

If the PEN of an attack is less than Armour Value AV of the target, the attack does not penetrate (but may still do some non-lethal damage). If PEN is greater than AV, the attack penetrates doing normal damage. If PEN is equal to AV, the attack penetrates but with a -4 modifier to the wound roll.

Since the penetration of bullets is largely dependant on velocity, and velocity falls with increasing distance from the muzzle, PEN for ranged weapons is affected by the range of the attack as follows:

For handguns and SMGs, PEN drops by one at every range band beyond Medium: -1 at Long (50-100m/yd), -2 at Very Long (100-200m/yd), and -3 at Far (200-400m/yd) and -4 at Very Far (400-800m/yd). Handguns and SMGs are

For rifles and machine guns, PEN drops by one at every range band beyond Long range: -1 at Very Long (100-200m/yd), -2 at Far (200-400m/yd), -3 at Very Far (400-800m/yd), -4 at Distant (800-1600m/yd) and -5 at Very Distant (1600-3200m/yd).

PEN and DC Range Modifiers

Range Band	Handgun/ SMG		Rifle/MG
	PEN	DC	PEN	DC
Contact	0	+1	0	+1
Point Blank (0-1m/yd)	0	0	0	0
Close (1-12m/yd)	0	0	0	0
Short (12-25m/yd)	0	0	0	0
Medium (25-50m/yd)	0	0	0	0
Long (50-100m/yd)	-1	0	0	0
Very Long (100-200m/yd)	-2	-1	-1	-1
Far (200-400m/yd)	-3	-1	-2	-1
Very Far (400-800m/yd)	-4	-1	-3	-1
Distant (800-1,600m/yd)	-5	-1	-4	-1
Very Distant (1,600-3,200m/yd)	-6	-2	-5	-2

As an optional rule, modern high-velocity rifle Ball ammunition should be treated as Soft Point (SP) from Point-Blank to Medium ranges (0-50m/yd), as at these distances the hyper-velocity bullet tends to yaw rapidly and fragment on impact [author's note: this is a rough approximation of reported observations].

The PEN value for shot (from shotguns or other weapons firing shot shells) is subject to the special rules listed under Ammunition.

Thus a 7.62mm NATO round (PEN 7) will penetrate a NIJ type III bullet-proof vest (AV 6) with full wound potential at up to Long range (0-100m/yd), with reduced wound potential from Very Long range (100-200m/yd), but will not penetrate beyond that.

For simplicity's sake, the PEN Damage Class (DC, see below) of large calibre guns (autocannon and artillery) and other powerful weapons are divided by five. These modified stats are called Structural Penetration (SPEN) and Structural Damage Class (SDC) and are equal to five points of regular PEN and DC. Similarly, vehicle and building AV is divided by five and referred to as Structural Armour Value (SAV). SPEN and SDC should be multiplied by five when used against human and animal targets, and SAV multiplied by five when hit by small arms.

Sloped armour: Sloping armour increases its effective thickness (and so AV) against horizontal attacks (i.e. from other tanks or ground units). Thus, 60mm of steel armour (or equivalent) angled back at 60 degrees has the same effective thickness of 120mm of the same armour set vertically.

AV and SAV for armoured vehicles is given as two figures (the second in brackets), plus a third figure in degrees indicating how far back from the vertical the armour is inclined (sloped). The first figure indicates the SAV for effective thickness of the armour against a horizontal attack, while the second indicates the SAV for the actual thickness against an attack from the optimal angle.

Without going into the maths of it, the table below shows (roughly) the how much you should multiply actual armour thickness by to get the effective thickness at various angles.

Angle from: Effective

Vertical Horizontal Thickness

0°-15° 90°-75° x1

30° 60° x1.2

45° 45° x1.5

60° 30° x2

75° 15° x4

80° 10° x6

Of course, you don't always have to attack horizontally. Aircraft in flight and infantry on top of buildings can fire down onto the exposed upper deck and turret roof of a tank. Troops in trenches can stick limpet mines to the bottoms of tanks overrunning their positions. This is where the second SAV figure comes in – it is used when the attack is launched from the optimal angle (perpendicular to the armour plate).

It should be pointed out that sloped armour offers no weight advantage over vertically-arranged armour. While the sloped plate is effectively thicker, it is also proportionately longer and heavier. However, sloped armour can partially or fully deflect projectiles, especially smaller calibre ones such as APFSDS, further increasing its effective thickness.

Composite armour containing layers of ceramics or glass (such as Chobham, Burlington, Dorchester, Combination-K and others) does not benefit from sloping, partly because an oblique impact is likely to completely shatter the ceramic or glass matrix, and partly because the plates are often as thick as they are high or long.

Small Arms

AV	Description	PEN	Example Attacks
0	Bare skin, light clothing	0	Punch, kick, club
1	Human skull, heavy clothing, leather, stab/slash/spike-proof clothing, padded jack/gambeson, horse or cow hide	1	Small knife/switch blade,, #4 to #12 birdshot, rock salt
2	NIJ Type I: ultralight ballistic cloth, chain mail, riot shield	2	Fighting knife/bayonet, machete, sword, .22LR, .32 ACP, .380 ACP, #3 to #FF birdshot
3	NIJ Type IIA/Russian Class 1: light ballistic cloth, steel helmet, medieval plate armour, ZSh-1 aramid fibre helmet, 1mm steel plate	3	.38 Special, .40 S&W .45 ACP, 9mm Makarov, #4 to #0 buckshot, shrapnel, grenade splinters
4	NIJ Type II/HOSBD HG1: US PASGT ballistic nylon helmet (tested), light covert ballistic vest, disguised ballistic waistcoat	4	7.63mm Mauser/7.62mm Tokarev pistol, 9mm Makarov AP, 9mm Parabellum pistol, 10mm Auto, .357 Magnum, .45 Colt, #00 to #0000 buckshot
5	NIJ Type IIIA/Russian Class 2/HOSBD HG2 and SG1: Russian Kazak-5 vest, US PASGT vest, ballistic nylon/kevlar helmet (claimed), Russian SPHERA-S titanium helmet, Russian MASKA-1Sch steel helmet, disguised ballistic jacket, standard ballistic shield	5	7.62mm Tokarev SMG, 9mm parabellum SMG, .357 Sig, .44-40 Winchester, .44 Magnum, 5.45mm Soviet, 5.56mm NATO, 12ga rifled slug
6	NIJ Type III/ Russian Class 3: Russian Kazak-4 vest, 6mm/¼” steel plate	6	7.62x39mm Soviet, .454 Casull, 9mm Parabellum 7N21 AP
7	Russian Class 5/HOSBD RF1: US Interceptor Body Armour, Improved Outer Tactical Vest (IOTV) and Modular Tactical Vest (MTV) with SAPI insert, Russian Kazak-6 vest, OMON vest, 8mm steel plate	7	7.62x51mm NATO, 7.62x54mmR Soviet, .30-06 Springfield, 7.62mm Soviet AP, 5.45mm Soviet AP, 9mm Parabellum 7N31 AP
8	10mm/⅜” steel plate	8
9	NIJ Type IV/HOSBD RF2: US Interceptor armour, IOTV and MTV with E-SAPI insert, 12.5mm/½” steel plate, heavy (wheeled) ballistic shield	9	.30-06 Springfield AP, 7.62x51mm NATO AP, 7.62x54mmR Soviet AP,
10	15mm steel rolled homogeneous armour (RHA) or equivalent	10	.50 BMG M8 API-T at 500m
11	17.5mm RHA	11
12	20mm RHA (15mm RHA at 100m/yd)	12	.50 BMG ball
13	22.5mm RHA (20mm RHA at 100m/yd)	13
14	25mm RHA (22.5mm RHA at 100m/yd, 20mm RHA at 550m/yd)	14	.50 BMG M2 AP, M20 API-T
15	30mm RHA (25mm RHA at 100m/yd, 20mm RHA at 1,500m/yd)	15
16	35mm RHA (30mm RHA at 100m/yd)	16	14.5x114mm, .50 BMG SLAP
17	40mm RHA (35mm RHA at 100m/yd	17
18	45mm RHA (40mm RHA at 100m/yd)	18	14.5x114mm AP
19	50mm RHA (45mm RHA at 100m/yd)	19
20	55mm sRHA (50mm RHA at 100m/yd)	20	14.5x114mm HEI-AP

Autocannon and Artillery

SAV	Equivalent thickness of rolled homogeneous steel armour (RHA)	SPEN	Example Attacks
5	60mm	5	40mm British Class S
6	70mm	6	37 x 263mm German BK 37 APCR,
7	80mm	7	30x173mm US, 37x195mm Soviet
8	90mm	8	47mm British Class P
9	100mm	9
10	110mm	10	57mm British QF 6-pdr, 76.2mm Soviet F-34
12	120mm	12
14	130mm	14	8.8 cm KwK 36 L/56 APCBC
16	150mm	16	100mm Soviet D-10 APHE, 122mm Soviet D-25 APHE
18	175mm	18
20	200mm	20
22	225mm	22	100mm Soviet T-12 APFSDS at 500m
24	250mm	24
26	275mm	26	100mm Soviet T-12 APFSDS
28	300mm	28
30	325mm	30
32	350mm	32
34	375mm	34
36	400mm	36
38	450mm	38
40	500mm	40
42	550mm	42
44	600mm	44
46	650mm	46
48	700mm	48
50	750mm	50
52	800mm	52
54	900mm	54
56	1000mm	56
58	1100mm	58
60	1200mm	60
62	1300mm	62
64	1400mm	64
66	1500mm	66
68	1600mm	68
70	1700mm	70

Cover

If you're too poor to afford body armour, or even if you're not, it's a great idea to take cover behind something solid during a gunfight.

Cover only protects you depending on the angle from which the fire is coming. A wall or a slit trench is no use if someone is shooting at you from directly above.

Cover AV

Cover type AV Cover type AV

Hollow wooden door: 1

Solid wooden door 2

Steel door: 5

Interior partition wall:

Thin wooden wall: 2

Log wall: 4

Brick wall:

Breeze/cinder block wall, single: 6

Breeze/cinder block wall, double: 9

Stone wall:

Light concrete wall (15cm): 12

Medium concrete wall (30cm): 18

Heavy concrete wall (50cm): 30

Sandbag wall, single layer: 6

Sandbag wall, double layer: 9

Tree trunk (15cm): 4

Car door/body: 3

Car windscreen: 3

Car wheel: 5

Car engine block:

Oil drum, empty, one side (1-2mm): 4

Oil drum, empty, both sides: 5

Oil drum, full of water: 25

Oil drum, full of sand: 9

Oil drum, full of (set) concrete: 25

Human body, front to back: 3

Human body, side to side: 4

Human body, top to bottom: 5

Layering armour and cover:

To calculate the AV for layered armour, take the layer with the highest AV as the base, and add one point for each additional layer.

The reason for this rule is that the relationship between AV and armour strength is not linear, but exponential: AV 2 is not simply twice as thick strong as AV 1, but more like four times as strong. Thus, wearing two bullet-proof vests one on top of the other does not double your AV.

Characters may stack two or three layers of armour, within reason. Only one layer can be something bulky like a flack vest or a steel breastplate (or any rigid or semi-rigid armour), and players and GM must use common sense to decide what is reasonable.

For example, a character who is really paranoid about getting shot might wear a light ballistic cloth t-shirt under a flack vest, with an oversized medium armour jacket over the top.

Cover AV also layers with the AV of worn armour, using the same rules. Multiple pieces of cover can be layered together.

Cover may often have a higher AV than any armour worn, in which case it is used as the base AV, and the +1 AV bonus for each further layer is added to it. Something that has just blasted through a foot-thick concrete block is unlikely to be stopped by a flak jacket.