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-   -   AP core Photo request - please help a student :) (http://forums.thecmp.org/showthread.php?t=59100)

Likon 11-09-2011 09:03 AM

AP core Photo request - please help a student :)
 
Gentelmen a have to ask you for help. I am a student of Warsaw University of Technology and I am writing a thesis for my Master of Science in Engineering degree. The topic is :"Evolution of armor piercing penetrators." I registered here because forum members here have milions of AP projectiles, and I am in need for photo documentation of 30.06 penetrator cores. It it one of the examples a write about and my promotor wants tons of photos of penetrator cores (he is a bit weird:rolleyes:). I have all the photos that I was able to find via google from this site and others.
Could you please post any and all photos of ap cores that you have in your posesion? American, canadian, AYR, FN any photos are highly aprreciated.
The cores that you have maybe from a sectioned bullet, or recovered from the target. If you know please write from what manufacturer the bullet was.(LC,DEN,AYR....)
MUCH THANKS in advance for any help !!!:)

raymeketa 11-09-2011 11:20 AM

Here is a photo of three AP bullets that I sectioned to show the cores.

Left is a Cal .30 (30-06) M2.

Center and right are bullets from the development of the 7.62mm NATO cartridges, showing two different core shapes and two methods of closing the base. The T29 was adopted as the 7.62mm NATO M 61 AP.

These bullets were all manufactured by Frankford Arsenal, U.S.A.
http://i41.tinypic.com/140aqvm.jpg

Likon 11-11-2011 12:43 PM

Mr. Raymeketa Thank you for the photo. I have found it earlier via google image search but thank you anyway.

It is nice to compare the better bullet to the crappy one. The one of many mistakes of US military when adopting ordnance. Choosing the inferior design...
Insted of adopting the shortened version of a battle proven m2 bullet with a by design stronger core they adopted the T29... And soldiers were with out a good AP for the 7.62nato...

raymeketa 11-11-2011 01:33 PM

I don't know if I'd characterise the adoption of the M61 as "crappy" or an "inferior design". The decision was made after several years of design and testing.

The current 7.62mm NATO AP is the M993 (M995 for the 5.56mm) which uses a completely different penetrator. If you don't like the M61, you'll like them even less.

Ray

Moonlitin 11-11-2011 02:14 PM

Here's a picture of some AP SL, 1943 bullets, and the cores I removed from them.

And a picture of the hole they left in the steel plate I shot them at.

Moonlitin

http://home.comcast.net/~t.vandyke/p...es/ap_core.jpg

http://home.comcast.net/~t.vandyke/p...es/ap_ammo.jpg

Likon 11-11-2011 09:29 PM

http://i1226.photobucket.com/albums/ee417/Likon1/ff.jpghttp://i1226.photobucket.com/albums/...Likon1/ap9.jpg
Mr. Moonlitin - thank you for the photos!!!

Mr. Raymeketa - for the m993 and m995: i like them if you can call it this way. I like them because off their superior performance. But it is obvious because they are different technology. Not much newer because FFV-Carl Gustaf was experimenting with tungsten carbide/cobalt cermetal AP projectiles in the 60`s, a couple years after the m61 was "born". Those prototypes where very similar in geometry to the now availible Nammo AP8 projectile (american designation m993). The Nammo AP3 (m995) was designed much later. These projectiles are leaps ahead of any steel core competition, but they are also currenty a bit obsolete. Nammo AP4 (5.56mm) and MEN DM31 both have better penetration especially at long range. Nammo AP9 (example of core posted above), MEN DM151, MFS2000 MM-FS (core above), Lapua AP492, all are competition for the m993, and all significantly outperform the m2, t6, t29/m61, fn p80, and all other steel-cores. Thats to be expacted. Modern tungsten carbide/cobalt (nammo is currently switching to iron/nickel binder) cermetals are superior penetrator materials in every respect (well maybe not the cost) to steel.
My dislike toward the t29/m61 originates from my opinion that the t6 was a better performing bullet, not that it was different from the "classic" m2 design.Well I didn`t find any data regarding the requirements of the US army when seeking an AP bullet for 7.62nato, but maybe if it required penetrating soft steel, aluminum armor, concrete, then the m61 can be better. But when it came to penetrating High Hardnes Steel ( or today modern ceramic armor ) the t6 was certainly better. Sir you see the m61 can penetrate softer materials better, because in short it has a sharper more pointed tip. The pointed tip ecounters less resistance when punching through these materials. They "flow" beside it. But that happends only when the material does not start to destroy, erode or shatter the core. In short if the hardness of the core seriosly overmatches the hardness of the target. When not the core is much easier to blunt than the t6. Its slimer, therefore has less structural strenght throught its entire lenght than the t6, which is technically a cylinder with a sharp cone and a boat tail. After impacting a high hardnes steel plate the sharp cone desintegrates and the core is virtually a cylinder, which is inherentlly stronger than a long cone in the t29 design. Machine a long slim cone and a cyllinder of the same diameter with a small cone. Hit them both with a hammer and see whitch is easier destroyed... The most importand thing when penetrating very hard targets is that the penetrator remains undeformed as long as possible. That is why tungsten carbide cored projectiles penetrate soo much better, not because of their density, or some "special properties of tungsten", but beacuse they are not so easily destroyed. Besides the core in t6 is around 1 gram heavier. That 1 gram is "integrall" to the core, and doesn`t disperse during impact like in the t29, which has a lead plug in the base to equalize its core underweight. During impact into a very hard object, the energy of the lead insted of being used for penetration is mostlly wasted when the lead material is diverged sideward by the hard core which is extremely fast decelerating on the hard barrier. It passes on some of the kinetic enrgy but most is wasted. The same phenomenon causes the m193 penetrate hard steel better at close range than m855. The energy is better transferred into the target with the m193 which promotes failure by shear plugging while in the m855 the lead core flows around the smashed penetrator which doubles the affected target area and no failure occurs. In the t6 design the core does all the work.
To get to the point : I am not suggesting that all the years of research where wasted on the t29. Maybe the army wanted a projectile that will defeat softer targets better. Or there were other reasons.
The US military solved many competitions, and research on new weaponry in sometimes weird outcome. For example: the competition for the new service pistol in the 80`s. We all know that the Beretta won but the SIG had two very important advantages: it was more durable with a high round count by means of its design ( the action locking into the ejection port system is well known for durabillity) and it was more ergonomic ( the Beretta is huge, I have relatively large hands but i shot the 92fs not very good... the trigger reach and the grip is too big). But the Beretta was cheaper, and in that time the USA wanted more political influence in Itally soo they let them won the contract and earn cash.
I dont know for certain fact what was the reason of adopting the m61, it was over half a century ago, Maybe some lobby, economy, different requirements? I am just speculating.

I appologize Mr.Raymeketa if I sounded rude or impolite disagreeing with you... I did not ment too. English is not my first language so it may sound this way. You are a very respected person on the net and i respect you also. Just wanted to state my different opinion on the topic.

Regards

raymeketa 11-11-2011 10:25 PM

Likon

It is obvious that you've done a lot of research in preparing your thesis. And your English is very good. There is no need to apologize for it.

You did not sound impolite, and it is not rude to disagree. Honest discussion is how we learn.

I believe that the M61 AP was adopted at a time when the role of armor piercing bullets was changing from what it had been during WW II. In the mid 1950s the US Ordnance Dept considered that the 50 Browning would be the cartridge to turn to when armor piercing capability was needed. The 7.62mm NATO was looked at as the cartridge to be used against personnel and light armored or unarmored targets. The ability to penetrate a helmet at 600 yards was one of the primary considerations when designing the ball bullets and the penetrating specification for the AP was not much higher, requiring less than 1/2" of armor penetration at 100 yards. The original 7.62MM ball bullet was the M59 which had a mild steel core but even that was short lived, being replaced by the M80 with a lead core, only 4 years later. I think the general feeling at the time was that the M59 nearly duplicated the M61 and there was no need for two cartridges so similar.

The M993 and M995 bullets still remain the standard for use against personnel and light armored targets but they do have enhanced penetrating capability, I think, as a result of experience in the Gulf Wars, especially against concrete and heavy earthen structures. But, as far as I know, the .50 BMG is still the primary cartridge when armor piercing capability is called for.

Here's a photo of the T21 steel core bullet (right) that became the M59 in 1955. The T11 was an earlier iteration.

Good luck on your thesis. You chose an interesting subject.

http://i42.tinypic.com/1z67gow.jpg


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