Depending on vehicle design, if the turret comes off, it is because the magazine has been hit. Now, most burning tanks you see recently are those Iraqi pieces of crap hit by American or British (I don't know what rounds the Brits use) M-829E2/E3 DU KE APFSDS. Translated from Man-Who-Sit-In-Large-Metal-Box Speak to English, that means:
M-829E2
or M-829E3 Depleted Uranium* Kenetic Energy** Armour-Piercing Finned-Sabot Discarding-Sabot.
* - Depleted Uranium is the **** they make the core (The rod that actually penetrates the tank's RHA and any applique armour***) out of. It's amazingly dense, but the funny part is that when the tank brews up (Kaboom, Kablam, "Insh'Allah, 72 Virgins and whatnot") it fragments, and actually turns into this nifty little radioactive dust that screws up the indigs (indigenous population) for a few generations to come.
** - Kenetic Energy. Go outside and punch someone. You are transferring KE from your fist to their face.
Edit:
- The more KE you apply on a smaller surface area (Like the penetrating rod from any APFSDS round) the better the penetration. Same reason you clench a fist. Less surface area, same or more power. Same reason you extend your fingers back towards your wrist before you land the "Karate-Chopping-Action" blow - straightens out the knife edge of the hand, reinforces it by tightening the muscle, and reduces surface area marginally.
To sum it up: There is a giant core of dense material ramming itself through a thick piece of metal that has a surface area of say two feet. The more SA, the more room for the stopping power of the material to actually stop the round. The less surface area, the same force, the same velocity, basic physics, the round is gonna penetrate. Then, if it doesn't shoot right through the vehicle, it shatters and screws everyone up inside along with pieces of the vehicle's interior; irregardless of applied Spall liner.
*** - RHA: Rolled Homogenous Steel. This is the stuff all base armour is made out of, with the exception of Post-1980 NATO vehicles. Ideally, the Hull and Turret are all RHA, or, post-1980 NATO, Chobham composite.
Applique armour is what you bolt ontop of the RHA. It can be anything from little ERA (Explosive-Reactive Armour: Very good at dealing with HEAT, HESH rounds in conjunction with a Spall liner****, not so much with KE Penetrator unless it's Russian Kontakt-5 or later.) plates to the giant MEXAS bricks that the Canadians stick on their outdated Leopard C2 tanks.
**** - HEAT: High-Explosive Anti-Tank. It "melts" the armour of the enemy tank where the round impacts the armour, and sprays the molten metals into the crew compartment. Needless to say, the crew and their vehicle become "less than operational" in a very short amount of time. HESH rounds work much the same way, but they shake off this giant piece of the interior and start beating it off the crew at a few hundred metres per second. They also, become less than operational. RPGs and all anti-tank weapons work off a HEAT principle. The Russians have actually developed a tandem-HEAT shell for their Post T-80U series that works as well as American M-829E2 APFSDS.
A Spall Liner is a magically little coating that goes on the interior of the vehicle. In conjunction with the base armour and any applique, it prevents large chunks of metal being shaken off the interior by any impact and beating the crew to death.
Anyways, and to be brief.
Every knocked out tank i have seen was remarkably intact except for the turret lying next to it.
I'm assuming Desert-Storm post-Desert Storm/Iraqi Freedom here. In which case we're looking at vehicles most likely killed by Hellfire AT missiles (HEAT system) or M1A1, M1A2 MBTs (DU KE system of killing the vehicle.)
In which case what we've got are hits to the turret or hull, both of which are immediately fatal to the outmoded tank's occupants. These are Iraqi vehicles, so they won't even perform as well as the outdated Russian T-55, T-72 systems. Either way, the magazine gets hit, ammo brews up, or the vehicle burns, and then ammo brews up. One way or the other, the turret takes a massive beating.
Most of the knocked-out vehicles I've seen have their turrets on, but beat to ****.
The Americans have this great tendancy to overstate the ability of their weapon systems based on an outmoded way of referencing basic target ability from past military engagements. To be brief again and explain it from the bottom-up.
1) The Russians are racist bastards. They do not like Muslims. Therefore, when the Iraqis came knocking and asked for some MBT systems, the Russians said, and I'll assume some things here:
"We're an Aethist state."
"But you have tanks that we can give you oil for."
"And you have your funny little religion."
"Here's oil. Can we have some tanks?"
The Russians went off in a corner (The Politburo) and said:
"Ivan. We can sell them cheap little pieces of crap that our forces can strip damn near everything off of and then get massive amounts of petroluem distillates in return."
"Boris. That is a good idea."
"Where is my Vodka?!"
"Here, Premier Yeltsin."
And suchforth. Yeltsin wasn't in power when the Russians sold the Iraqis (They call them Sand-******* too...) the T-55 and T-72 tanks.
2) What did the Soviet Army do to these tanks? Well, they stripped off the ERA and then stuffed it onto BMPs (An APC) and discovered that:
"It don't fucking work."
"What do you mean it doesn't work?"
"The seams, where we weld the vehicle, they burst when the ERA activates to engage oncoming threat."
"Bullshit."
"Here, Comrade Lieutenant. You can watch from inside vehicle."
"**** that ****, Comrade Senior Sergeant. I'll watch from out here."
"You are wiser than you look."
"To the GULAG with you!"
"Not without my Vodka!"
And suchforth.
3) Then the Iraqis let them rust for a while, barring when they beat the Hell out of the Kuwaitis and the Iranians with them, with a little help from Uncle Sam's Biochemical weapon stockpiles.
4) Then Saddam stopped doing what he was told. America laid the smackdown on his ass in '91, using M1A1 tanks. They believed that the M-829E2 APFSDS in conjunction with their Hellfire and TOW missiles and suchlike were the ultimate weapons system. They're not, but they're still damn good.
5) The Americans then went on to believe that based off these statistics, their vehicles were better than any extrapolated data on the T-80 series could support. As such, the ego of their tankers swelled until they couldn't fit their heads inside the Combat Vehicle Crewman's helmet.
Using Operation Desert Storm and Operation Iraqi Freedom as an example of what their weapon systems are capable of, they discount the current capability of any former Warsaw-Pact indigenous (Non-Export) main battle tank post 1972.
6) Then the Russians discovered:
"Oh ****! Those Sand-****** bastards live in Chechnya too! Oh ****! We must attack them!"
Then the world discovered how effective ERA is against RPGs, when T-64BVs (Made in 1964, outfitted with first generation ERA) are taking fifteen, twenty hits to the front and flanks of the vehicle with RPGs without blowing up. Then a Chechen Mujahid said:
"Screw that. Let's shoot it up the ass with one of these babies."
Then the T-64BV blew up, and that's all the world remembers about Grozny '92. Nothing important. For the record, the Russians have never lost a T-80 in Chechnya. That's about eight years of fighting, not one T-80 has been lost due to enemy fire. Usually the tread throws itself off and the Russians end up abandoning it. :roll:
"No honey, I really wasn't looking for that! It's got a really neat bomb video on it! I mean it, you know you're the only bombshell I need though..." or "well princess, some women just aren't as classy as you and your mother... who doesn't need to know daddy was even at that site... no, no, no... there's nothing wrong with, well maybe... Hey, who wants a pony?" Really though, a little warning next time please! Some of us don't need help earning a night on the couch.
Well, now that you're there, I suggest you get really drunk. Have a morning to match the night, that's what I always (Just now) say. Yes, I've had too many. Yes, I'm making it sound like "Wino-Central" again. No, I don't hold Mele responsible. No, you can't legally either. Why? Because we all clicked 'yes' for that little checkbox that absolves him of all legal responsibility! Whoooooyah!