What are the internal and external ballistics of the 5.8x42 Chinese?


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jlbraun
March 25, 2008, 02:24 PM
Does it act more like a 5.45 and tumble internally, or does it fragment?

What is the muzzle velocity and energy? Ballistic coefficient?

What's the bullet construction?

Military designation?

Case construction?

Help appreciated. I have some theories that I would like more support on.

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Tony Williams
March 26, 2008, 12:27 AM
There are two loadings: the "light" loading for the assault rifle and LMG, and the "heavy" loading for the DMR and GPMG.

The standard ball bullet weighs 4.15g and is fired at velocities of 790 m/s (326mm carbine barrel), 930 m/s (463mm assault rifle) and 970 m/s (557mm LMG). It has a hardened steel core and is in fact an AP type, penetrating around 10mm armour at 300m. It tumbles, as do all pointed bullets, but does not fragment. The Chinese have given body-armour penetration a higher priority than wounding effect.

The heavy ball weighs 5.0g and is fired at 895 m/s (590-620mm barrels). It has a smaller steel penetrator but more lead to increase the weight. The bullet has a better BC for improved long-range performance.

Cartridge cases are steel, lacquered brown. The chamber pressures are very low, being only 41,500 psi for the standard ball.

elmerfudd
March 26, 2008, 12:49 AM
That's pretty respectable ballistics. I went ahead and did some rough conversions. The 4.15 gram bullet is about 64 grains. Out of a 13" carbine it's traveling a little over 2600 fps and out of an 18.5" rifle it's around 3100 fps. Out of the 22.5" LMG it's hitting 3230 fps.

Heavy ball weighs 77 grains and is moving out at right around 3000 fps.

My conversions might not be perfect, but they're within 2% or so.

Ergosphere
March 26, 2008, 12:56 AM
out of an 18.5" rifle it's around 3100 fps

How does it get such a high velocity with only 41.5 kpsi pressure? :confused:

elmerfudd
March 26, 2008, 01:15 AM
It is pretty impressive, isn't it? I rechecked those calculations and this time got exact conversions. The barrel length is actually 18.23" and the velocity 3051 fps.

Of course it could be that the figures are a little optimistic or perhaps the pressure figures got misinterpreted.

Deer Hunter
March 26, 2008, 01:17 AM
Much like how most rifles on the internet are .2 MOA capable?

R127
March 26, 2008, 02:23 AM
I find it difficult to believe that it will defeat over 3/8th of an inch of hardened steel at 300 meters with only 2300fps and 750ftlbs. I can tell you that real 7.62x39 AP will only penetrate about half an inch of non-hardened steel at 50 yards. The velocity and energy between the 7.62x39 AP at 50 yards and the 5.8x42 at 300m are not far off. I would expect a little better performance from the Chinese round but not that much! Even at close range the velocity and energy are looking a lot like 5.56x45. M855 isn't true AP but 1/4 inch of hardened steel armor plate will stop pretty much any number of those rounds close in. Even at point blank range I'd find 10mm of armor plate a bit of stretch... I could believe it would perform near that level against a mild steel plate but that's a whole nother animal entirely.

PTK
March 26, 2008, 02:44 AM
R127

You're talking about a larger diameter round. The smaller diameter the projectile, the easier time it has getting through armor.

Ergosphere
March 26, 2008, 02:57 AM
Bullet composition and design have a large effect on penetration capability, as well.

Tony Williams
March 26, 2008, 05:22 AM
The penetration figure seems about right to me. The tungsten-cored 5.56mm M995 penetrates around 15mm/100m, and the general rule of thumb is that tungsten gives you roughly a 50% increase in penetration over hardened steel.

The case capacity is quite a bit more than the 5.56mm, as well as the calibre being larger, which accounts for the lower pressure. Loaded up to 5.56mm NATO-like pressures (let alone Mk 262) this would be one hot performer.

Yute
March 26, 2008, 06:13 AM
Still corrosive too...

R127
March 26, 2008, 12:36 PM
You're talking about a larger diameter round. The smaller diameter the projectile, the easier time it has getting through armor.

That is true but at 50 yards the 7.62x39 has a lot more energy than the 5.8x42 at 300 yards. Actually it has nearly twice the energy so I was not very precise earlier when I said the energy numbers were close but what I meant was that the 7.62x39 should have enough of an energy advantage to offset it's larger diameter, we're only talking about 1/10th of an inch here. Either way hardened steel is more often defeated by velocity than energy and we're still talking about the 5.8x42 rolling along at 2300fps which ain't exactly screaming. Like I said M855 isn't really AP but it does have a hardened steel penetrator nub and if it can't do .25" of hardened steel at 3100fps pointblank I just can't see 5.8x42 being able to do 10mm with 2300fps even if it has a larger penetrator. Like I said the M855 at 3100fps doesn't really do any real dammage against .25" hardened steel, just some superficial surface marking.

I don't have any personal experience with M995 but I can say it is doing around 2900fps at 100 yards which is nearly a 25% improvement over the 5.8x42's 2300fps at 300m. I've also heard that the M995 does closer to 12mm of hardened steel at 100 yards which would be nearly 1/8th an inch of difference. Tungsten is certainly a lot denser than steel and it's some very hard stuff but without more velocity and energy to back it up it just doesn't sound right. I'm not saying it's a problem with Tony i'm just saying that I suspect the published stats on the 5.8x42 are off.

Tony Williams
March 26, 2008, 12:56 PM
There's a pretty exhaustive article on the 5.8x42 by Timothy Yan in the 11th edition of Cartridges of the World. This gives a lot of performance data including comparisons with 5.56mm and 5.45mm. This states (among other things) that the light load has 100% penetration of a NATO A3 steel test plate at 300 metres (as does the 5.56mm P112 steel-cored AP - but not the M855). The size of the wound cavity in ballistic soap is, OTOH, markedly inferior to the 5.56mm and 5.45mm. His info came from an article in Small Arms, a Chinese magazine.

R127
March 26, 2008, 03:42 PM
Do you happen to know the specs for the NATO A3 steel test plate? I did a little quick searching but found more noise than signal. I'm particularly interested in hardness and yield strength.

CBS220
March 26, 2008, 04:01 PM
41.5 kpsi and 3200 fps? I'll believe it when I see it...

R127
March 26, 2008, 04:22 PM
There's a topic in general discussion right now that has the lame stream media saying 7.62x39 is a high velocity cartridge. Doing some quick checking it looks like the SAAMI spec for this round is 45,000psi and it does around 2350fps out the muzzle. .223 is more like 55,000psi. I could believe the 5.8x42 could make high velocity with low pressure but not out of an 18" barrel. I think the Chinese source may have printed some errata or propaganda. To put it in perspective I once watched a Chinese wushu martial arts exhibition. It was pretty normal until a representative from the Chinese military came out in his camo uniform and started breaking boards with his mind. :rolleyes:

Tony Williams
March 26, 2008, 11:31 PM
If the Chinese data is supposed to be propaganda, why would it show the wounding effect to be considerably less than the 5.56mm?

R127
March 27, 2008, 12:45 AM
Why can't it be errata? Why anything? Until we get some we will never know. :confused:

Tony Williams
March 27, 2008, 12:49 AM
Well, it's not just one data point in which there might have been a typing error. Velocities for different barrel lengths, plus curves of velocity over distance for both the light and heavy loadings, have been published. So if there is any error, it is most likely to be in the chamber pressure, since that is just one figure.

[edit to add: I don't see the armour penetration as being wrong, because the data says it is comparable to a 5.56mm steel-cored AP, which is what I would expect from the ballistics.]

elmerfudd
March 27, 2008, 01:01 AM
I agree about the chamber pressure. All their other figures were in metric units, and here is this one unusually low figure in English measure. Many foreigners really have no clue when it comes to English measurements.

Tony Williams
March 27, 2008, 05:21 AM
Having said that, the pressure of the 5.8mm should certainly be noticeably lower than that of the 5.56mm, since the muzzle energy is not much higher yet the case capacity is clearly greater (10.5mm wide instead of 9.5mm) as well as the calibre being bigger. What I don't have is a programme for working out from those factors what the chamber pressure is likely to be.

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