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Penetration Value and Resistance

The lowest values of weapons Penetration Value (PV) are based on the scale of damage done to human body tissue, but this scale can be extended to apply to more damage resistant armors. Rather than use the existing body armor classification, I will make a direct comparison between the PV of a weapons round and the Penetration Resistance (PR) of a given type of armor. A round with PV higher than a given armor's PR should penetrate that armor, doing damage to whatever is behind. A round with lower PV will not penetrate that armor, and will do less damage than its rating typically allows. Using the data points:

  • PV: 6 rounds can penetrate inch (6.35 mm) steel armor plating; Given on the PV scale, this information implies that such an armor plate has a PR of 5
  • PV: 25 rounds can penetrate 635 mm of steel armor plating; This point has been chosen for a convenient end result, but is also motivated by MDC issues that will soon arise.

Constraining a logarithmic function to these points gives me an effective thickness of steel armor plating for a range of PR values. The values I am currently using are displayed on the table to the right.

PR for Different Materials

Different materials will have a different relation between their thickness and PR value. Many properties of a material will effect its relative value for use as armor plating of varying thickness, but I will assume a simplified model. Different materials will have a thickness multiplier, allowing a comparison of the relative PR of a given thickness of that material to the same thickness of steel armor plate. For example, common hardwood will have a multiplier of 25 %. This means that a given thickness of hardwood will have the PR of armor steel with 25 % of that thickness.Two inches (50.8 mm) of hardwood will have a PR of 8, equal to the PR of a half inch (12.7 mm) of steel armor plate.

Generic MDC material seems to have approximately ten times the damage capacity of high strength steel. This leads me to make the approximation for MDC thickness multipliers: 1000 %. Ten centimeters of armor plate steel will have the same PR, 17, as one centimeter of MDC armor plating. This, like most aspects of this system, is a number that may change in the future, but does seem to function well on the PR scale I've developed.

Some thickness multipliers that I've determined (for the time being) are:

  • Soft wood, plaster, standard glass: 12.5 %
  • Hardwood, plexi-glass: 25 %
  • Brick: 33 %
  • Concrete, cinder block: 50 %
  • Reinforced concrete: 67 %
  • "Super" metal alloy: 250 %
  • Standard MDC material: 1000 %

PR Used with Human Bodies

It seems appropriate to apply the idea of PR value to a human body, since the original PV scale is defined by a round's potential to damage that human body. Unlike armor plating, humans have both SDC and Hit Points. The potential for complication in this system is great, and many options for use suggest themselves:

  • SDC of character is treated as armor, while the Hit Points are treated as an armored object. A typical human's SDC has a PR of 2, meaning weapons with PV greater than 2 will do some amount of damage to a character's Hit Points. This PR value increases by one point for every 50 SDC points, to a maximum of 6.
  • Character's body is treated as a version of armor plating. A round will go through the entire body if it is sufficiently penetrating. This means less damage is done to the body, and the round may strike an object on the other side. PR of the human body: 4, +1 per 50 SDC points.

When and if these options should be used is difficult to determine. I would say that the first option is appropriate for unarmored characters facing less penetrating weapons, and the second is appropriate for other situations.

Developed by Dan Steiner
Last Updated: 10/24/01

 

PR

tsteel(mm)

tmdc(mm)

1

2.53

0.25

2

3.18

0.32

3

4.01

0.40

4

5.04

0.50

5

6.35

0.63

6

7.99

0.80

7

10.06

1.01

8

12.67

1.27

9

15.95

1.60

10

20.08

2.01

11

25.28

2.53

12

31.83

3.18

13

40.07

4.01

14

50.44

5.04

15

63.50

6.35

16

79.94

7.99

17

100.6

10.06

18

126.7

12.67

19

159.5

15.95

20

200.8

20.08

21

252.8

25.28

22

318.3

31.83

23

400.7

40.07

24

504.4

50.44

25

635.0

63.50

26

799.4

79.94

27

1,006

100.6

28

1,267

126.7

29

1,595

159.5

30

2,008

200.8

31

2,528

252.8

32

3,183

318.3

33

4,007

400.7

34

5,044

504.4

35

6,350

635.0

36

7,994

799.4

37

10,064

1,006

38

12,670

1,267

39

15,950

1,595

40

20,080

2,008

41

25,280

2,528

42

31,825

3,183

43

40,066

4,007

44

50,440

5,044

45

63,500

6,350

46

79,942

7,994

47

100,641

10,064

48

126,699

12,670

49

159,505

15,950

50

200,805

20,080