LTC G

Yankee Dog, I would question the authority of one source, especially since the next line says: "One recent theory that would help explain this is that the jet has a molten core but with a solid outer sheath." So apparently it is molten? Your article is merely a cut and paste of other articles so it is hard to get anything definitive out of it. Most sources state that the mechanisms of a shaped charge jet are not fully understood. However, every article has agreed with the following: "Explosive energy is released directly away from (normal to) the surface of an explosive, so shaping the explosive will concentrate the explosive energy in the void. If the void is properly shaped (usually conically), a high-velocity jet of plasma will form." Caveat - I am not claiming to be an expert (but I did stay at a Holiday Inn Express last night) on shaped charges, I think you need a PhD. to fully understand some of these articles. I personally have trouble accepting the solid theory since it would not seem to account for spaced armor defeating shaped charges. I would think only a liquid or gas would expand into the annular space. If it were a true solid, like a long rod penetrator, APFSDS, then spaced armor would not work. The theory above about a molten core with solid-behaving outside works for me - maybe we're both right. Glenn

Flamingknives, Shaped charges are indeed a plasma jet. By definition, plasma (in physics) is gas that is so hot it is stripped of its electrons. I have fired many a shaped charge into the ground(for cratering charges) there is cerainly nothing solid at the end of the hole and it is quite hot. If it remained solid, you are implying that it penetrates kinetically, which wouldn't make sense since a shaped charge works better the slower it is going. Take a look at some knocked out WW2 tanks and you'll see where it does melt through the armor and splatters the interior of the vehicle. As to the other comment. It would matter greatly whether an object was liquid or not upon impact. A liquid is incompressable and would expand out along the path of least resistance. Energy is still transferred, but deformation would be minimal. That's why we use fire hoses instead of sandbalasters for crowd control!

Juan, As someone else pointed out, even the SVD sniper rifle failed to penetrate a soldier's body armor at fairly close range. Remember, the SAPI plates only protect the chest and upper abdomen, there are still plenty of places our soldiers get shot and killed, although it is usually a bleed-out, not instant kill. The neck and groin and especially vulnerable areas which we do protect with soft Kevlar, but that will not be effective against rifle fire. We suffered some KIA in Iraq through the round entering the chest through the armpit or down through the neck, but those were freak shots that you can't really do much against. Glenn

Mr. Flamingpicky, Being a degreed engineer, I try to avoid using highly technical terms when describing things because most people just get lost. An EFP is a platter charge, not a shaped charge as most people misconstrue. The platter's used by the Iraqi insurgents are typically 4-6" in diameter and "soften" to a slug about 3/4 thier original diameter. Molten was not to imply liquid, which is a state the metal does not reach, otherwise it would splatter against the vehicle armor. A shaped charge forms a plasma jet of superheated gas which melts metallic armor. While this works well against a tank or IFV, it has little effect against the thin armor of a HMMWV. I'd much rather be hit by a shaped charge rather than an EFP when driving around Iraq. Good discussion. Glenn

Dirtweasle, The news reports about troops buying body armor are either old or bull. All troops receive body armor including the latest SAPI plates. There was a problem in the first year of the war, but that has long been solved ever since that famous question in Kuwait. There is a problem with different manufacturers claiming that their armor is better and they should be allowed to sell it to troops. The Army has gone to the extent of banning any non-regulation armor. The logic is that we don't want to create an "arms race" amongst troops who will go out and spend $1000 on something that some magazine says is the latest greatest stuff, but isn't necessarily and then everyone else wants that too. I'll admit, it didn't do a lot for morale when the Marines issued a recall notice on their body armor last year, but told all the troops that their armor was fine. My understanding is that the Marines are now going to a slightly different armor (Dragon Skin), but there really isn't any significant difference. Just as an aside, the hardest thing to do with your armor on is reach for something. Can't really put the butt of your weapon against the shoulder either, so the upper bicep just takes the bruises.

Mr. Battlefront.com, To expound on your points: Fatigue has less to do with weight than training. What do you want to bet that I can strap a 55 Lb. ruck on my back and yet still beat you in a 5K race? Why, because I train to a high physical standard (my 5k run time is 21:56-not bad for a 46-yr old). You generally will not find that amongst third-world armies or a guerilla force. Boron Tetracarbide ceramic plates are issued to every soldier and most civilians in Iraq. The military calls them SAPI (Small Arms Protective Insert) plates and cover the chest and upper abdomen front and back. Currently being issued are side SAPI plates. The front and back plates each weigh about 10 pounds apeice and the side plates are supposed to be another 5 each. Yes, it's a lot, but no one turns down protection. Note that individuals do not have the choice of what to wear with the exception of a few SF guys. The key function of the side plates is to help protect against IEDs and VBIEDs (Vehicle-borne IEDs) which generally strike the side of a vehicle and can puncture the kevlar only side of body armor. VBIEDs are the most dangerous thing to us since you can load a 1000 lbs. of explosive into a truck or car as opposed to an IED constiting of an artillery shell. The kevlar by itself is good for fragmentation and ammo up to 9mm. The SAPI plates are rated to take 7.62 NATO ammo for four hits (in different areas aobviously) per plate. As to your categories of fire, I would suggest the following threats to a soldier: 1. Debris from and explosion. Sand and gravel flying around will cut up and stun, but not generally disable a soldier. Does creat a lot of blood though. 2. Small fragmentation. Can be stopped by body armor and vehicles easily, but will disable exposed arms and legs. 3. Large Fragmentation. Not to sound defeatist, but there is essentially nothing that can protect you from large fragmentation except vehicle armor. It does not even have to penetrate your body armor to simply impart enough kenetic energy to remove your head or cause hydrostatic shock to your internal organs. 4. Small arms. This can range from the AK round (7.62x39 to 5.56x54(?) and is frankly all about the same. The NATO round has better penetration due to its higher velocity. Neither can penetrate U.S. Body Armor and both can penetrate an unarmored body, so I don't see any difference, except possibly for acting against a steel helmet. 5. Blast. This includes RPGs as well as our latest nemisis in Iraq - the EFP (Explosively Formed Penetrators) which is a platter charge able to penetrate anything less than an Abrams. This forms a molten slug out of the platter and will take out the drive and front passenger of a HMMWV while leaving everyone else essentially unharmed. Obviously, body armor menas nothing in this context. Hope this helps - always glad to share my experiences. Glenn

Hey, everyone. I'm new to this forum and found this tread interesting and thought I'd share my knowledge. I just returned back from a year in Iraq and did my senior thesis on ballistic armor when I earned my engineering degree, so I know a thing or two. As has been already pointed out, body armor is rated at four levels, some of which have sub-levels. Even within those levels, the actual protection can vary through improvements. When I deployed to Iraq in May 2005, we were issued the new SAPI plates which were still Level 4, but supposedly worked better (and were noticably lighter) than previous models. Still, it does weigh a lot, but I think people do not understand operationally how this affects the soldier. Much is made about the weight (my armor with attached gear and ammo (120 5.56mm and 45 9mm) weighed 42 pounds. This sounds like a lot, but you must remember that for years the Army has trained to be light infantry and go everywhere with an 80 lb. ruck on their back. With a few rare exceptions, we don't hike in Iraq. We need to move far, we take HMMWVs or Blackhawks (camoflage has become useless). If anything the game should have a fatigue factor for long operations on foot such as occurred in Fallujah. But it's really not as bad as people make it out to be - just make sure your Camelback is full before you go out! As far as this high-tech ammo you guys are talking about, it doesn't exist as far as I know. Our 5.56mm is green-tipped, except for a few tracer rounds which are orange-tipped. My understanding of the steel core is to cause the 5.56mm to be a "wounding round". This core cause the bullet to tumble, yet stay together once in the body and cause much more damage. There are documented cases of a round entering the neck and exiting through the ankle! We learned our lesson in Korea about rounds that go straight through the body - they don't stop the enemy. One more thing to claify is the nature of modern body armor. In simple terms, aramid Kevlar can absorb a great deal of energy through plastic deformation (think rubber band). This work well with low speed pistol ammo and fragmentation, but not against high speed rounds or, ironically, knives. The high-speed round snaps the fiber before it is able to deform. The solution to this is putting a layer of very hard material in front of the Kevlar. The material commonly used is Boron Tetracarbide, a ceramic that is one of the hardest substances known. The bullets impact with this hard material send a shockwave back through the body of the bullet causing it to fragment along with a section of the ceramic plate. This fragmented mass can then be caught by the Kevlar and absorbed the energy without cutting the fibers. My SAPI plates were supposed to be good for four hits, although I never had to test this out. If anyone has any questions about Iraq or body armor, I'll be happy to answer them. Glenn