5.45x39 vs 7.62x39

[beerslurpy]

Damn, I wish I could find it... Oh I CAN find it! The Wolf FMJ has a huge airspace, probably bigger than military spec. Note that many of the rounds with small airspaces (like the ULY EM1) yaw extremely well.



from left to right, the current 7.62x39 rounds:
Ulyanovsk EM1 match (my fav round, accurate and yaws quickly)
Klimovsk FMJ,
Klimovsk "Silver Bear" FMJ (Identical),
WOLF FMJ (note gigantic air gap),
Barnaul FMJ,
Uly FMJ,
Early Klimovsk FMJ,
Rare early brass cased TCW fmj.

[Joejojoba111]

That's awesome!

One quib, I don't understand why air-gaps cause yaw? I remember reading something (sorry I haven't read the links yet but I will) in a book that said NATO was concerned that the hollow-tip on 5.45 would increase wounding, but it didn't? It just increased penetration?

Does the lead still shift forward upon initial impact? That would (in my mind's eye) cause the bullet to penetrate straight further. If the lead Doesn't shift, then I can see why it would yaw more.

And the Bananna curve, I don't get that either. (I'll read the links!)

[beerslurpy]

Nothing shifts. It is purely weight distribution.

Think of the bullet as a spinning top. The more top heavy it is, the quicker it falls over. The bullet decelerates slowly in air, but decelerates very quickly in flesh or water. This causes the static (im)balance of the bullet to overcome the dynamic balance induced by the spinning. Its like taking a spinning top on a tabletop and increasing the force of gravity by 4-fold.

However there are probalby other factors like protrusions on the bullet, etc. I have no idea why certain non-airgap bullets yaw well.

The banana shape is just from the bullet going sideways and getting squished as one form of energy transfer between the body and the bullet. Since much of the bullet is empty space and soft lead, it squishes more easily than say, a steel ball.

NATO and the Soviets both misunderstood the reasons that the M16 was causing such severe wounds in vietnam and mistakenly attributed it to tumbling. It wasnt until some years afterwards that Fackler discovered it was actually fragmentation. The AK74 causes more damage than if it were shaped like a lawn dart with all the mass at the front of the bullet, but that isnt a bullet design I have ever seen seriously contemplated.

[clange]

From what I understand, commercial ammunition is not loaded with the hollow cavity that the military round is. Wolf is supposed to be the closest to military spec, but none of the commercial ammo is loaded the same as the military stuff.

I think the guys on AK47.net claim that wolf 5.45 FMJ does have the air pocket.

[AK-74me]

I guess you know what I would pick!

[Number 6]

I think the guys on AK47.net claim that wolf 5.45 FMJ does have the air pocket.

Hmm, I stand corrected. Everything that I have come across indicated that commercial 5.45 does not have the air pocket.

Beerslurpy, those are all 7.62x39 rounds, do you have any cutaways of the 5.45 round?

[clange]

Well i went back and found the thread. A few guys said yes, one guy said no, and the last guy blamed the "no" on soft lead and poor cutting, claiming the weights would be far different if there were no air pocket. Who knows.

http://ak47.net/forums/topic.html?b=4&f=64&t=71491

[Clean97GTI]

5.45x39

The poison bullet gets my vote. I believe the Afghan's called it that because it seemed to kill very well. It does make nasty wounds and penetrates just fine. Higher velocity and flat trajectory is what I want.

If I'm gonna shoot something in 7.62, its going to be my Mosin-Nagant...and thats 7.62x54R.

[The Grand Inquisitor]

I was under the impression that the 5.45 was dubbed the "poison bullet" not because of some chimera effect of causing disease, but because of its ability to destroy tissue after impact.

[Tomac]

It's 5.45 for me: less weight, less recoil, flatter trajectory and more accurate.
The Wolf 60gr 5.45 does have the airpocket, I've cut several open myself to verify. It weighs appx 5gr more than the military 7N6 because denser lead replaces the hardened steel penetrator. There was a commercial 70gr load made awhile back (can't remember the mfgr) that didn't have the airpocket. The Wolf 60gr 5.45 yaws *very* quickly and the core sliding asymmetrically into the airpocket can cause a radical change in the bullet's path. Ex: I hit a 1-gal water jug high center front at 50m. The bullet exited low left rear after shredding the jug.
Tomac

[beerslurpy]

The steel core is a cost saving measure. The bullets did not pierce steel plate any better than lead core.

[MTMilitiaman]

Hmm that is interesting. I didn't know the 7.62mm Wolf FMJ had that airspace but it does...I just confirmed it with a pair of pliars and a hacksaw. Neato. Now I want to do all sorts of tests.

Good discussion guys keep it going.

[clange]

http://www.btammolabs.com/fackler/wo...ary_rifles.pdf

Those of you who havent read these articles, please do. I am sick of people spouting old wives tales about tumbling poisoned bullets and backing up flawed arguments with rumors instead of facts. Not trying to accuse, just inviting you all to read the articles and be informed. Pretty please.

Correct me if i'm wrong, but the 5.45 looks like its almost completely sideways in as little as 10 cm. How is that not effective tumbling?

I'm not saying the 5.45 is a magic bullet that will go in your knee and come out your ear, but it appears to do what people claim it does, yaw very quickly. It may not wound as bad as 5.56 at the proper velocity, but even in the second article he says 5.56 is unlikely to fragment on a target over 200m, and thats out of the long barrel of an M16A1. (this may not be the case anymore, i dont know. He also says this is the M193 bullet, but later says the M855 would be similar. I dont even know whats currently used, so again this may no longer be true, dont know)

On extremities it would be more apparent, the 5.45 would have a tiny entrance wound, and a big hole where it came out sideways. The 5.56 (and 7.62) may have a small hole on both ends. I can see where some may start thinking differently about a bullet when it looks like a 22 hit them, and a golf ball came out (like in the image of the pigs leg).

When everything works, it looks like 5.56 is deffinately better, but i wouldnt call the 5.45 a "lol disappointment" either.

[Curare]

The many airspace filled, comercially available 7.62 rounds pictured, throw this argument into a different direction.

Do we have terminal ballistic data on these--these can't behave as poorly as the nondeforming 7.62 miltary rounds discussed in the linked articles.

[beerslurpy]

Yes, clange, it does yaw very effectively, and as Fackler's tests and countless combat injuries show, yawing does not produce wounding close to that caused by fragmentation.

The increased temporary stretch cavity from the yawing does damage certain organs very well, but there is no substitute for a large permanent cavity, which the 5.45 does not produce and the 5.56 does.

Modern 7.62x39 yaws as well as 5.45, penetrates barriers much better and produces larger permanent wound channels. The 150gr soft tips wolf sells now are probably comparable to regular hunting ammo as shown on page 4 of this article. Note the enormous permanent (and temporary) cavity from a 150gr soft nose 7.62x51 (800 more fps than the wolf 150gr AK ammo).

Oh yeah, lets not forget bullet fragmentation.

[clange]

I can see that fragmentation causes a more serious wound from the diagram, my point (or observation from reading the article) was simply that it has to fragment to accomplish it. If velocity is low, or it passes through too little tissue its not as effective.

And i think most know that soft point and hollow point are more effective than FMJ, but seeing the diagrams brings a new level of understanding. Thanks for all the links.

[beerslurpy]

Basically all that yawing gets you is slightly larger wound channel and if you happen to be near a vulnerable organ like the liver or a full bladder, it could possibly do big damage from the temporary stretch cavity.

Fragmentation gets you everything that the temporary stretch cavity does, only filled with fragments that will damage flexible tissue instead of just rigid tissue. All of that damage causes massive blood loss, which in turn causes loss of consciousness through drop in blood pressure. Its like taking out the oil plug on a running engine vs taking the entire oil pan off while it is running. Both ways will get you to lose oil pressure and spin a bearing, but one will do it a lot faster than the other. "Pulling the oil plug" is even less effective on a human because small wounds will quickly seal due to coagulation while large ones will continue to bleed for longer.

I'm probably going to give wolf 150gr SP a try when I run out of ULY EM1. Current indications are that it is even more accurate than the 123 gr FMJ, probably due to increased BC.

[Tony Williams]

From 'Assault Rifle: the Development of the Modern Military Rifle and its Ammunition' by Max Popenker and myself (details on my website):

"When a bullet passes through a human body, it creates permanent and temporary wound channels. The permanent one is slightly wider than the bullet and is the source of most of the injury, the temporary one is wider still but usually closes quickly without causing much damage. The first generation of jacketed military rifle bullets at the end of the 19th Century had rounded noses and parallel sides and were quite stable, following a straight path through the body. This created a very narrow wound channel, with a strong probability of the victim making a quick recovery provided that no vital organs were seriously damaged, and this earned such bullets a reputation for ineffectiveness.

However, as we have seen, modern pointed bullets are inherently unstable because their centre of gravity is much closer to the base than the tip. They will therefore tumble end-to-end on entering a body, before settling down to travelling base-first. This tumbling creates a far wider permanent wound channel (widest where the bullet is travelling sideways in mid-tumble) and is responsible for most of the injury caused. In contrast, commercial hunting bullets are designed to expand on impact, which greatly increases the size of the wound channel, but these are illegal for military use; tumbling achieves a similar effect in a different way. The rate at which a bullet tumbles depends on a number of factors, mainly concerned with the size, shape and composition of the bullet. The British .303 inch Mark VII ball round, used in rifles and MGs in both World Wars, had a light-alloy tip filler, thereby producing a stronger rearward weight bias which caused more rapid tumbling. This was the subject of criticism from Germany, who argued that it was against the spirit of the international Hague convention of 1907 which banned bullets calculated to cause unnecessary suffering.

Other things being equal, small-calibre bullets tend to tumble faster than larger ones, which partly accounts for the reputation for effectiveness achieved by the 5.56 x 45 NATO round. Both M193 and M855 bullets usually start tumbling about 10 cm after penetration and take another 15 cm to complete the manoeuvre. The 7.62 x 51 M80 ball tumbles more slowly, starting at around 15 cm and taking a further 25 cm to complete. The rate of tumbling for the 7.62 x 39 varies considerably depending on the type; the Russian steel-cored ball at first just yaws between 25 and 30 cm and does not complete tumbling until about 50 cm after impact, whereas the Yugoslav M67 bullet, which has a lead core with a hollow tip (and therefore a stronger rearward weight bias) tumbles much more quickly, starting after only 10 cm. The 5.45 x 45 ball (which also has a hollow tip) follows a similar pattern to the Russian 7.62 x 39, except that it commences yawing after only penetrating about 5 cm and has finished tumbling after about 40 cm. It must be stressed that these are all average figures when fired into an homogenous ballistic gelatine designed to mimic accurately the response of human flesh. What actually happens when bullets strike the decidedly non-homogenous human body may vary considerably, and there have been combat reports of 5.56 mm bullets passing straight through a body without tumbling.

Incidentally, it is often stated that the 5.45 mm's hollow tip is designed to bend on impact to encourage tumbling, and this has been demonstrated when the bullet is fired into plasticine (and sometimes occurs when it hits a human target). However, this does not happen when fired into ballistic gelatine. The hollow tip is probably there to keep the weight down despite the bullet having a long, slender nose for external ballistic reasons. It also provides a useful rearward weight bias. One experimental bullet type specifically designed to encourage fast tumbling was the Lőffelspitz or spoon tip, invented by Dr Voss when working for CETME, which has an asymmetric tip; this doesn't affect the external ballistics.

If the bullet hits an unprotected body, it is likely to be most effective if it completes tumbling within about 30 cm, as this is similar to the average thickness of a torso. This may appear to favour the small-calibre rounds, which generally tumble within this distance. However, if the bullet hits something else first (e.g. the enemy's arm) then the bullet will start tumbling before hitting the body, and in these circumstances the 7.62 mm bullets are likely to perform better. Furthermore, small-calibre bullets are more easily stopped by obstacles such as ammunition magazines kept in chest pouches, as has been demonstrated in tests. In any case, the basic wound channel created by the bigger bullet will clearly be larger than with the small calibres, other things being equal.

A further degree of injury occurs with bullets which break up under the stress of tumbling, the multiple fragments heading off in different directions and adding significantly to the wounding effect. Most bullets do not break up, the most famous ones which do being the 5.56 x 45 loadings, both M193 and M855. The US M80 7.62 x 51 does not break up, but the German equivalent has a thinner jacket with a cannelure (a knurled ring around the centre) which does break up and probably inflicts the most severe wounds of any modern military rifle bullet. It should be noted that bullets which strike bone may also cause much more serious injuries, as the bone fragments can act in much the same way as bullet fragments.

The importance of fragmentation to the effectiveness of the 5.56 mm bullets has a bearing on some of the criticism aimed at the current short-barrelled US M4 carbine. Fragmentation only occurs at high impact velocity. The barrel of the M4 is only 14.5 inches (368 mm) long rather than the 20 inch (508 mm) barrel of the standard M16A2, which reduces the muzzle velocity to the point where fragmentation only occurs at very short range. In the normal 510 mm (20 inch) barrel the maximum fragmentation distance is around 150-200 metres (the longer distance being for the M193), but in the short carbine barrels it can be as low as 50-100 metres. However, fragmentation is an accidental effect rather than a specific US military requirement, and it appears that different bullet production batches may perform differently, with some failing to fragment; serious criticisms were expressed about the effectiveness of the M855 'green tip' bullets used during the American action in Somalia. There are also reports from Iraq of combatants continuing to fight despite being hit in the body several times by 5.56 mm bullets at very short range.

The controversy over the effectiveness of the M4 appears to have stimulated the development of improved loadings. The heavy (77 grain / 5.0 g) Mk 262 5.56 mm loading was originally designed for accurate long-range target shooting, but has been found to tumble well and fragment at much lower velocities than the current service rounds. It was used by US Special Forces and the USMC in Iraq in 2003, and may well be adopted more widely. More radically, a new 6.8 x 43 cartridge is being considered, of which more later."

Tony Williams: Military gun and ammunition website and discussion forum

[c_yeager]

With 5.45 you are pretty much stuck with Russian produced ammunition that only comes in a couple of flavors. This is fine plinking but, i like to have some options. WIth 7.62x39 you get a WIDE variety of loaded ammunition along with the option of handloading anything you want. Unless something has changed recently there arent any options for reloading 5.45 at all.

[MoeMentum]

I vote for 7.62x39. I can see the holes better from the firing line.

[Tomac]

Not all 5.56 FMJ will fragment and 5.56 fragmentation was an accident, not designed. The jacket has to be thin enough and the cannelure deep enough coupled w/sufficent velocity for fragmentation to occur.
Tomac

[klover]

One of the silly sks rifles I bought came with a Lee die set. Guess I'll achieve
framentation the old fashion way: soft points.

So what bullet diameter do I need to order to fit the bore of a VEPR K?

[Onmilo]

Me
7.62X51/.308 first.
5.56X45/.223 second.
7.62X39 third.
5.45X39 forth.
But that's just me,,,,,

[rbernie]

So what bullet diameter do I need to order to fit the bore of a VEPR K?

.310 (Hornady and Speer) or .311 (Sierra) will work just fine. The Hornady 123's are said to have the fastest expansion and jacket fragmentation. Not so great for hunting, but maybe just the ticket for anti-personnel use.

I would recommend that you stay in the 123gr-125gr bullet weight range. The 150gr bullets give up too much velocity, IMO.

[jobu07]

I dont' care if it yaw's, fragments, does loop-de-loops, or see-saws. I wouldn't care to be shot by any of them!