What happened to AKM lethality?

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[MikeyD]

Do you mean close-range targetting occupants of buildings from the outside, or actual melee fight in the rooms? If there's a difference between weapons at extreme close range its kind'a hard to tell. The weapon goes full auto and everyone dies! :eek:

[Sgt.Rock of Easy Company]

Im pretty sure he means firing from outside into a building. Like penetration of rounds into the building and killing people.

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[Battlefront.com]

Hi Adam,

No clue Just confirmed with Charles that the AKM should have a slightly better penetration rate (though not stellar and certainly not less) compared to the smaller "modern" small arms rounds.

What kind of tests were you doing?

Steve

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[Battlefront]

There are still a lot of uncontrolled variables in there. What two squad types are you using? Are the soldiers exactly the same in both type and number other than the difference of holding an AK-74 vs AKM? What other weapons are involved that might be skewing the results (e.g. RPD, RPK, SVD)? I'm not sure CMSF even has two squad types precisely "equivalent" like this.

Certainly for starters I can tell you that the AK-74 guys will have substantially more ammo than the AKM guys because their rounds are smaller and lighter. They can "spray and pray" for a longer time than the AKM guys can. This is important because when firing into a well-protected target (like a building) you have to expend a lot of ammo to do some damage. The AKM guys will simply run short earlier than the AK-74 guys do.

As a general rule, better Syrian troops carry the "74" series of small arms while the lesser troops (e.g. militia, reserves) carry the older "47" series. There are differences between these forces beyond the small arms, even if you're already correcting for experience levels. For example, the body armor they have (or don't) often differs.

There are a lot of potential differences here that are probably not possible for you to control when picking a couple of squads from the TO&E, and these are the likely factors you're seeing take effect in your tests, not differences in wall penetration capability.

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[YankeeDog]

Another thing to consider with whether, at that very close range, the cover isn't strong enough to stop either round type.

It's a bit unclear to me exactly what kind of construction the various buildings in CM:SF are meant to represent, but at short ranges like 20m, even an AK74 round will have no trouble penetrating your typical wall made of single-course cinderblock or brick. Heavier buildings with concrete rebar etc. would be another matter.

But it would seem to me that if the cover involved isn't heavy enough to stop either round type, it's simply going to come down to who can put more pieces of lead downrange, faster. And here, the lighter, easier to control on full auto, higher ROF weapon (i.e., the AK74) is going to win.

If my hypothesis is correct, there should be a "sweet spot" at longer ranges, where the AKM round will reliably penetrate the exterior wall, but the AK74 round won't. In this range band, you should see a substantial advantage to the AKM.

Cheers,

YD

[Taki]

@Steve: Is there a Real Ballistic Model for Small Arms Fire and is every Bullet calculated or is there an Abstracted System like in CMx1? Can you explain it?

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[YankeeDog]

Originally posted by Adam1:

Let's not overcomplicate it though. Test results that used to have the AKM squads win now have them lose, that's all there is to it.

Yes, but you also have to make sure you're not oversimplifying, to make sure you don't arrive at an erroneous conclusion.

For example, maybe rather than the AKM being "nerfed", what's actually happened is that the cover offered by typical building walls has been reduced, so now both 5.45mmx39mm and 7.62mmx39mm rounds penetrate easily at close range.

Pure speculation on my part. But it's important to look at all the angles and consider all the variables. Something has obviously changed in the modeling. But it's not necessarily the AKM terminal ballistics.

Cheers,

YD

[MikeyD]

I don't know how many patches ago this happened but I believe BFC took forum members' advice and increased the max range of the M4 and AK74 by a bit. If AKM guys are losing more often it might be because their opponents' bullets are carrying a bit farther and more accurately than previously.

[Pandur]

i didnt play into 1.07 so far, will do it soon beside the problems with my graphics card.

what i can say without haveing played 1.07...

YankeeDog

actually in 1.06 the houses got slightly reinforced.

MikeyD

i think adam ran the tests at generally low ranges. the upped max range shouldnt do any difference there.

and last but not least, there was a test video posted, it was well documented and looked like "official" data.

it was called "Concealment does NOT equal cover". you can see it on you tube.

it showed that the 7.62x39 ball was still superiour in penetrating the test object on the given range, when compared to the tested 5.56 round. not to forgett that.

[Battlefront]

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 ]

[c3k]

Charles,

Wow. It is wonderful to see this kind of information. I, for one, appreciate you posting it. Thank you. Now, get back in your jar!

Regards,

Ken

[Mishga]

What a post!! Loved the technical aspect. Please, Sir? can I have some more?

[John Kettler]

Charles,

Hello and thanks for this!

Are you modeling the fact that the M4A1 and the unlisted SAW's bullets have a hardened steel insert in them placed there specifically to defeat body armor? Does your model take into account that the M16/M4/AK 47 and similar can take down a cinder block wall by chewing it to bits, even absent a clean penetration? IOW, do you model progressive degradation of such medium cover?

I wouldn't characterize the AK-74 projectile as hollow point. What it has is a core which slams forward into the nose on impact with flesh, causing the bullet to tumble, achieving the same effect that the M-16's original bullet obtained by virtue of being a reworked varmint round and therefore readily upset in its trajectory when it hit something. I have seen no data whatsoever on how well the AK-74 does in terms of absolute cover penetration, let alone relative to the AK-47. Do you have any info on this, please?

Regards,

John Kettler

[Taki]

Thx for that Values Charles and for the Insights in the Game MEchanics.

I still want to know if there is an Abstracted Small Arms Modell or every Bullet is counted? As you stated above that Bulltes will fly trough Windows and Doors there must be a Ballistic FLightpath for every shot fired right?

But on the other Hand: How can it be that Bushwacker fires so close to enemy Pos that i need so much shots to kill him?

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[Flanker15]

But what about that video that everyone has probably seen "concealment is not cover" where a M16/SAW is unable to go through a brick/cinder wall but an AKM shoots straight through? Or is the AKM in CM:SF hollow point aswell?

[Cantabron]

When you say 5.56x39 I suppose you mean 5.56x45 NATO right?

[Battlefront]

Re: Body Armor

The protection provided by body armor in CMSF is reduced by a factor related to the "armor" penetration capability of the round striking it, in much the same way (though simpler) that we handle anti-tank shells hitting tanks. In other words, body armor won't do much to stop a .50 caliber round.

Re: Progressive degradation of cover

We simulate this abstractly. That's why you see a broad range of percentages for the bullets penetrating building cover in my previous post, instead of a more black-and-white yes-or-no answer to "does this bullet penetrate?".

Re: Absolute data on cover penetration

Nope, we don't have any either. This sort of thing is really hard to find, and even if we could locate some, I doubt we'd be able to do a reliable direct apples-to-apples comparison between all the different ammo and gun types and cover types we have in the game. So instead we base the game equations on known data like bullet mass, caliber, velocity, and other factors like steel core, etc.

Re: Is every bullet counted?

Yep! It wasn't in CM1, but in CMSF we count 'em all. Even so, it takes an enormous number of bullets expended to cause each enemy casualty in real modern warfare (on average). Of the top of my head I remember estimates for this from Vietnam and it was something literally in the tens of thousands of bullets fired for each enemy hit.

Re: M4A1 vs AKM

Adam - if you have specific information concerning M4A1 rounds not penetrating cover well please let me know. I can make adjustments if necessary. Actually I just saw a bit on Wikipedia saying that the M4A1 ammo can potentially shatter on impact if the striking velocity is above 823 meters/sec. This would reduce penetration capability at close range where the bullets are fast (and we saw the same phenomenon at work with British 2-pounder and Sherman 76mm AP shells in CM1) so I will look into it.

As for the AKM not shooting through walls very well, please state precisely why you think it should be able to do so. It's a relatively slow, lightweight, "short" round. Those characteristics do not make for good penetration capability. It's possible that the M4A1 penetration should be reduced (due to potential shatter effects) but I do not see any reason why the AKM penetration performance should be increased.

Re: 5.56mm x "39"

Oops, typo, yes that should be "x 45". I edited it above.