The best possible weapon to take on a tank is another tank. No army with any choice in the matter would rely entirely on the infantry’s anti-tank weapons. But the various infantry weapons make it possible for infantry to not be completely helpless against tanks, and have the advantage of numbers and cheapness. It’s sort of like in the Middle ages when armored knights ruled the battlefield: archers and men with polearms could and did take down knights, but you wouldn’t want to field all infantry against a force of armored and mounted knights.
[sidebar]It’s posts like this that keep me coming back to the SDMB. Nobody else has the range of participants we have here![/sidebar]
Individually, not very. But when used often enough, in enough situations, against a variety of targets, the odds catch up.
The USMC’s AAVP7A1 is very vulnerable, especially since it is chock-full of Marines (20-some of them.) However, I don’t think that one has yet been lost in action. The Bradley is much better off, with it’s armor generally working as advertisted. The M1-series are rather amazing, given the amount of RPG hits these things are absorbing. Still, even the mightey M1-series does have weak point. If you shoot enough RPGs at a M1, odds are you will eventually hit one of those weak points.
A British Challenger 2 tank, during the early days of the war, took dozen of RPG hits. Didn’t even knock it out of action. To think, those almost went to Iran 
(Well, the Challenger 1.)
The HEAT-warhead projectiles would be pretty bad weapons against infantry, in most situations, since the explosive force is so concentrated ‘forward’. There are fragmenting warheads and hyperbaric (fuel-air explosive) warheads, however, that are darned usefull vs. infantry.
Vs. a HUMVEE, they will of course penetrate right through, but that is also a disadvantage: There is generally no ammo to ‘cook off’ in a HUMVEE (not like in a Bradley or Abrams), and unless the stream hits a person, you are unlikely to cause catastrophic damage (to people; The hummer is unlikely to survive.) Most effective vs. a ‘soft’ target like a HUMVEE would be traditional high-explosive.
It is interesting to note that the Stryker brigade over their is reporting very positive things about the Stryker, and it’s ultra-super-high-tech armor vs. RPGs: Basically, a ‘net’ of metal (so-called Slat armor), not dissimiliar to a fence, stuck around the Stryker. RPG hits the ‘armor’, and detonates prematurely. Yet another gift from the British. (I think it was them, years ago, that came up with the concept of ‘slat’ armor to defeat HEAT warheads.)
I was under the impression that there is a reactive armor kit for almost every armored vehicle. Also, many mechanics are very resourceful so what is to stop them from adapting elements of one kit to the features of another armored vehicle?
You can find a number of discussions on the incident referred to by the OP and similar incidents at the AFV News Discussion Group at the AFV News site (AFV=Armoured Fighting Vehicle). In this case, the RPG was apparently fired straight down into the top of the turret from a highway overpass, injuring the two crew members who had their heads sticking out of the turret hatches from the surface blast and fragments. The RPG penetrated the thin top armour on the turret, which is NOT designed to be RPG resistant.
The MI tank is very resistant to attacks from the frontal arc, but has thinner armour on what are normally areas not exposed to direct attack by serious weapons, such as the rear and top. It is not invulnerable. Tank design is a process of compromise, where you increase the armour on the front by decreasing the armour elsewhere, while still trying to keep the weight within reasonable limits. The goal for the MI, which was met pretty well based on actual experience, was not to make the tank invulnerable, but to make it very difficult to penetrate from the front (where most of the attacks come from on a normal battlefield) and to maximize crew survivability when it was penetrated.
It is not that hard to knock out an M1 (or any tank) if it is hit in the right place. For example, as the rear of the M1 is basically a huge engine grill, it is not that difficult to penetrate the armour there and kill the engine (this happened to at least one M1 in Iraq, apparently to a stray 25mm round from a US M2 Bradley). However, the crew will normally escape and the tank can be hauled back to the workshops and the damaged engine pulled and replaced in a few hours. Similarly, a hit in the ammo storage racks at the back of the turret will blow off special armour panels before the explosion can penetrate into the rest of the turret, again sparing the crew and resulting in a workshop repair job rather than a destroyed tank.
Most of the destroyed tank pictures coming from Iraq are the result of hits that started fuel fires, which are very difficult to extinguish and will usually cause the tank to be completely burnt out. This is apparently usually due to hits on the fuel cans carried on the outside of the turret for refueling the auxilary power unit (small electrical generator) or on the APU itself on earlier models of the tank. Newer models have the APU in a self contained installation under armour to avoid this problem (part of the original design but dropped due to Congessional cost-cutting, IIRC).
The was an incident a couple of months ago where an RPG hit the side of an M1 right at a “golden BB” location, where it passed through a miniscule gap above the armour skirt hanging outside the track and hit a thin spot in the armour on the inside of the track. it went through, cut a track through the back one crew member’s flack jacket and the front of the seat pad he was leaning against, and then hit the fuse panel on the other side of the tank, knocking out the electrical system. Again, no serious injury (the tank commander had a couple of burns from the hot metal spray), and the tank was repaired and put back in action.
As northern piper said, pick away. Very neat extra information.
And to allow you to continue to pick… is the heat from the explosion too low to melt the copper, the duration of the explosion too short to allow enough heat to transfer into the copper to melt it, or the pressure high enough to keep it solid?
Short of matt’s return I’ll stick my neck out and say that at the pressures present at shaped charge detonation everything inside the shock cone is going to be a solid. The time and energy constraints you mention, BoringDad are way too constrictive to allow a massive transfer of heat. Plus that massive psi overburden tends to be a bit of a bitch.
Side point to the discussion. Without an explosive charge, the appropriate equation is momentium = mass times velocity (p = mv)
MonkeyMensch: spot on about the heat transfer! Detonating explosives are surprisingly bad at starting fires from their own heat of detonation.
The penetrator will be heated by the physical work done on it, but not to the melting point of copper or steel. Solid penetrators can be recovered - reportedly they have a final shape reminiscent of a short fencing sword with a disc hand guard.
Experiments with other possible liner materials have included lead, for that extra bit of density, and glass. Lead, that soft squidgy metal, shatters at the deformation rates involved in lined cavity charges and doesn’t form an effective penetrator. Glass on the other hand forms a penetrator nicely. Go figure!
(Since glass is of lower density than copper or steel, it’s surprising that anyone bothered to run the experiment. My WAG is that the feasibilbity of using glass liquor bottles with hollow conical bases for field-improvised charges was being studied.)
Basically, Hand Grenades work by exploding at the enemy. RPGs work by distracting them because they’re trying to level up their party so they can change character classes before the boss battle, so you can get close enough to throw a grenade at them.