Bullets and Buildings

[James]

I was wondering if anyone could give a rough ballpark estimate of how much protection buildings give against small arms fire. Wood/Brick against smg/rifle/mg calibre rounds.

[womble]

Not really. You can state a few guidelines.

• Barns provide near-zero protection. They're not even very good concealment.
  
• Modular buildings are tougher than the other kind.
  
• SMG rounds don't work as well as "proper" full-charge rifle rounds. "Carbine" rounds (including 7.92K) are somewhere in between.
  

After that, "it depends" on too many variables really to give any more precise advice.

[Bulletpoint]

I never understood what is meant by "modular" buildings, could you explain please ?

[womble]

Look in the editor.

[Mord]

Modular buildings are like a construction set. You can combine buildings to create bigger buildings, or buildings with more shapes, or place them separately and just have a single building.

Mord.

[slysniper]

In other words, you never know for sure how well the bldg gives cover until you see the bullets bounce off it or you have a great memory what every bldg looks like. Some mod and single bldgs can look very similar.

Churches are about the best and in general, the bigger the structure, the better the cover tends to be.

Small buildings provide little cover and as mentioned barns, very little.

On them type of structures, it is best to stay behind them instead of inside them to get some benefits in protection

[A co]

Also in some cases, if not all, the appearance of wood or brick is just cosmetic and doesn't affect cover.

[Bulletpoint]

Also in some cases, if not all, the appearance of wood or brick is just cosmetic and doesn't affect cover.

That's actually really good info. Never knew that. Thanks. Would be nice if "what you see is what you got"...

[Felix_45]

Was there not a mod that identified modular buildings? Or am just imagining things.

[MikeyD]

As a general rule of thumb the physically larger the building type the more resistant to fire it was made in the game. Cathedral pieces are virtual fortresses. CMBN buildings had been made very tough owing to the largely stone and masonry construction in the area. There had been requests during the Beta to dial it back for CMRT due to the high proportion of wood buildings. Perhaps Charles did, I don't really know for sure. But a lot of Russian building at the time weren't 'stick construction', they were closer to stout log cabins. So even a wood structure would be more protection than todays particle board, insulation and drywall separating you from the elements.

[Chops]

The following is a post from Charles regarding CMSF, just to give you an idea of the kind of detail modeled. It would be great if Charles would post this type of data for the WWII games as well.

I thought you guys might find some of the inner working of CMSF interesting as it pertains to this thread, especially because it's been updated for v1.08. Here's how CMSF rates the following weapons for their ability to penetrate a typical CMSF building's outer wall at various ranges.

CMSF buildings are considered to be "medium" strength. They're not rickety old shacks but they're not stone or concrete bunkers either. Keep in mind that CMSF allows shots to go through windows and such in buildings too, so we're only looking at the chance to penetrate the building wall here.

You may notice that sometimes penetration is better at longer ranges. This is due to the "shatter gap" experienced by projectiles striking the target at especially high velocities.

Weapon: AK-74

Muzzle velocity (m/sec): 900

Round: 5.45mm x 39

Round Weight (g): 3.25

Chance to penetrate CMSF building: </font>

• 0m: 4%</font>
• 100m : 13%</font>
• 200m : 0%</font>
• 300m : 0%</font>
• 400m : 0%</font>
• 500m : 0%</font>

Notes: This round has a (sort-of) hollow point, and the front of its core is lead, not steel, so it penetrates less capably than it otherwise could.

* * * * * * * * * *

Weapon: AKM
Muzzle velocity (m/sec): 710
Round: 7.62mm x 39 (actual diameter is 7.9mm)
Round Weight (g): 7.97
Chance to penetrate CMSF building: </font>

• 0m: 31%</font>
• 100m : 16%</font>
• 200m : 0%</font>
• 300m : 0%</font>
• 400m : 0%</font>
• 500m : 0%</font>

Notes: The 7.62x39 round used by the AKM is not a "standard" rifle bullet - it's smaller and lighter. It packs less punch than a typical WW2 rifle round, for example. It's much closer to the "kurz" ("short") round fired from the infamous German MP44 of WW2.

* * * * * * * * * *

Weapon: PKM

Muzzle velocity (m/sec): 825

Round: 7.62mm x 54R (actual diameter is 7.9mm)

Round Weight (g): 9.58

Chance to penetrate CMSF building: </font>

• 0m: 34%</font>
• 100m : 41%</font>
• 200m : 34%</font>
• 300m : 24%</font>
• 400m : 8%</font>
• 500m : 0%</font>

Notes: Ah, now that's more like it. This was the standard Soviet rifle cartridge of WW2. It's the same diameter as the round from the AKM, but the PKM fires this one with a higher velocity, plus this round is heavier because it's longer. Higher velocity and greater mass hitting the same-sized target area yields greater penetration.

* * * * * * * * * *

Weapon: M4A1
Muzzle velocity (m/sec): 905
Round: 5.56mm x 45
Round Weight (g): 4
Chance to penetrate CMSF building: </font>

• 0m: 10%</font>
• 100m : 0%</font>
• 200m : 10%</font>
• 300m : 0%</font>
• 400m : 0%</font>
• 500m : 0%</font>

Notes: A very high muzzle velocity and a heavier projectile (compared to that of the AK-74) suggest that penetration ought to be pretty decent at short range. However, the bullet is constructed such that it often shatters upon impact at high velocity, reducing the expected penetrative performance. There is a noticeable shatter gap too.

* * * * * * * * * *

Weapon: M240

Muzzle velocity (m/sec): 853

Round: 7.62mm x 51

Round Weight (g): 9.56

Chance to penetrate CMSF building: </font>

• 0m: 37%</font>
• 100m : 44%</font>
• 200m : 39%</font>
• 300m : 33%</font>
• 400m : 23%</font>
• 500m : 8%</font>

Notes: Similar to the PKM, but with a little extra power from a higher muzzle velocity and a round that is essentially the same mass but has 7% less cross-sectional area.

* * * * * * * * * *

Weapon: M2
Muzzle velocity (m/sec): 899
Round: 12.7mm x 99 Mk211 AP-incendiary
Round Weight (g): 43.48
Chance to penetrate CMSF building: </font>

• 0m: 86%</font>
• 100m : 81%</font>
• 200m : 86%</font>
• 300m : 82%</font>
• 400m : 78%</font>
• 500m : 74%</font>

Notes: Ma Deuce doesn't play around.

* * * * * * * * * *

Weapon: KPV

Muzzle velocity (m/sec): 1005

Round: 14.5mm x 115 BZT

Round Weight (g): 59.56

Chance to penetrate CMSF building: </font>

• 0m: 100%</font>
• 100m : 100%</font>
• 200m : 96%</font>
• 300m : 91%</font>
• 400m : 87%</font>
• 500m : 90%</font>

Notes: Ma Deuce's Russian cousin is even bigger and badder.

[ March 09, 2008, 12:14 PM: Message edited by: Battlefront ]

[womble]

That's not the whole story, though, because once a bullet has penetrated and its trajectory has intersected some poor pTruppen's delicate pixels, the pTruppe gets a "terrain save" which is easier to make in tough buildings than it is in Barns.

[James]

Interesting stuff guys, thanks.

[womble]

As ever, elevation also matters. Shooting down into a building negates much of the cover provided at windows. Shooting upwards increases the cover. Both simply by the geometry of the shots.

[Kauz]

I was wondering if anyone could give a rough ballpark estimate of how much protection buildings give against small arms fire. Wood/Brick against smg/rifle/mg calibre rounds.

I can NOT talk for the game...

In real life it depends on a lot of things:

- kinetic energy of the round at the moment of impact

- material it is made of (examples: copper, lead, steel, hardenend steel, tungsten),

- cross sectional area (45 ACP has a bigger one than 7,62mm

-construction (massive core or several mantlets; it is completly different if you use a expanding round (popular example: Dum Dum) or an armor piercing full mantel jacket tungsten-carbid round

-form (sharp like a 7,92X57 IS "sS" or flat like a 0.45 ACP)

- impact angle (at 45° your geometrical armor increaseing is about 40% of the original thickness, at 60° it is 100%)

- material-type you wanna penetrate (a water included medium is much harder to penetrate for a high velocity round with cavitation effect than for a low speed round without this effect)

- thickness of the medium you wanna penetrate (may be the round looses kinetic energy far faster in the medium after a nutation effect established while flying through a thicker medium)

But to give you an idea what you may can achieve due to some numbres and fast extrapolations:

Pistol rounds:

The are used in pistols (for example P38) and submachine guns (PPSH, MP40, Thompson).

They all have about 500 Joule (kinetic energy at the start):

The absolute maximum you might achieve is...

@100 meters a 9mm Parabellum round (kinetic energy

is then 270 Joule):

1 mm steel; 2mm iron, 28mm concrete (not reinforced i guess), 72mm brick (wall), 66mm sandbag (dry!), 138mm pinewood (dry!), 138mm soil/earth (natural evolved)

Rifle rounds:

The are used in Rifles (example K98k), semi automatic rifles (example SVT40, Garand or G43), battlerifles (FG42) and light, medium, heavy machine guns (like Maxim, DP28, L/H MG34/42, BAR)

They have something between 3000-5000 Joule (bigger example: 7,92X57 IS SmK(H) ~4900 Joule).

Standard might be something between 3500 and 4000 Joule (example 7,92X57 IS "sS" ~3700 Joule)

The absolute maximum you might achieve is...

@100 meters a 7,92X57 IS "sS" round (kinetic energy

is then 3208 Joule):

5 mm steel; 10 mm iron, 121 mm concrete (not reinforced i guess), 364mm brick (wall), 304mm sandbag (dry!), 850mm pinewood (dry!), 607mm soil/earth (natural evolved)

Medium rounds:

They are used in Assault rifles (StG44/MP44) and "carbines" (M1A1 carbine).

They have about the half kinetic energy of rifle rounds (~2000 Joule).

In case of the StG44 it might be convinient to just half the penetration power of the above given rifle round. (example: 2 - 2,5 mm steel.....50-60mm concrete....)

Remember: the softer, thicker and more wet the medium becomes....the more the penetration prognosis i have given you becomes wrong (especially the soil/earth or a wet tree/wood which is not included here).

And remember...i do not know what kinetic energy is left after a possible penetration. Some Nato sources estimate that a shrapnell (very evil wounds because of the wild forms) still has to have about 80 Joule to be deadly with high probabilty ....so in case ...especially of low speed rounds without cavitation-effect you should keep in mind that you need more energy in reserve.

And keep in mind that these numbres are for angles about maximum 30° if i had it right in mind (~10% geometrical thickness increasment)