ExTank wrote:
I take it they have to load the gun with some kind of anti-aircraft round (with shrapnel/flak, a proximity fuse, etc.) if they want to use it in this role. I’d be pretty hard-pressed to hit an airplane or a helicopter with an anti-tank round!
The Rheinmettal M256 Anti-Tank Cannon is a pure smoothbore, just like a shotgun. The spin is imparted by the round itself after the encasing sabot drops away.
The “bulge” you see in the gun tube (actually the thermal shroud) is the Bore Evacuator, a vacuum system designed to trap excess bore gasses, and prevent them from entering the turret once the “afcap” is ejected. The 120mm uses a self-consuming cartridge case, with a metal base holding the propellant igniter. The round is fired electrically, with the recoil operating the breech and ejection mechanisms. The metal base (about the size of a large ashtray) is referred to as the “after cap”, which was shortened in everyday usage by tankers into “afcap”.
If the 120mm system has a fault, it’s the ammo’s vulnerability to moisture damage (a round composed of chemically treated cardboard will be like that.)
Chobham (correct spelling) Armor was originally developed by the Brits in the late '60s/early '70s. We (the USA) developed our own brand of the stuff (we think that it’s better), but I’ve never heard of it referred to as anything but Chobham Armor. Some that I have known have alluded to some secret alph-numeric designation for the stuff; I was more concerned that it would actually stop the bad guys tank rounds (“Bad Guys”=people shooting at me).
Whether or not the M-1’s armor will stop it’s own 120mm DU Sabot I have no direct personal knowledge or valid scientific studies to cite; I suspect that in a full frontal hit, it will, and have heard anectdotes to that effect from other DS/DS vets.
I know for fact that it will stop a 125mm Sabot from a T-72.
Tracer: no special rounds are used; the HEAT-MP-T round is preferable (High Explosive Anti-Tank, Multi-purpose, tracer), but is a bit slower and less accurate than the DU Sabot round.
Obviously, frontal or acute oblique shots are better, but the sights are gradiated to allow massive amounts of deflection for full-flank shots.
Fixed-wing fast movers are very problematic, but rotary wing attack craft are more vulnerable than they think, at least to the M1 with a well-trained crew.
Sofa King: I followed your link and read most of the article. I say most because I really have no disagreement with the bits that I did read. Essentially, he was saying much the same as I have (or the other way around if you prefer): Armor, in whatever form technology, resources and the tactical environment demand, will never be obsoloete, and new design will have to be adapted to meet changing battleground environments. Nothing new or suprising there.
Light tanks, medium tanks, heavy Main Battle Tanks. Whatever the perceived strategic and tactical environment demand.
Like I said earlier: The M1 family may very well become superfluous; as technology advances, the design itself will certainly become obsoloete. 
But the ability to use maneuver and massed firepower from behind the protection of armor to break not only the enemy’s resistance, but also their will to fight, will only become obsolete when war iself is obsolete.
Whether it’s super-infantry in Power Armor ala Heilein, super-tanks ala Drake, Armored Walkers like Battle Tech or Star Wars, or close-support orbital bombardment from space cruisers and such, there’s no such thing as “too much firepower”.
ExTank
“Mostly Harmless :P”
The Rheinmettal M256 Anti-Tank Cannon is a pure smoothbore, just like a shotgun. The spin is imparted by the round itself after the encasing sabot drops away.
The “bulge” you see in the gun tube (actually the thermal shroud) is the Bore Evacuator, a vacuum system designed to trap excess bore gasses, and prevent them from entering the turret once the “afcap” is ejected. The 120mm uses a self-consuming cartridge case, with a metal base holding the propellant igniter. The round is fired electrically, with the recoil operating the breech and ejection mechanisms. The metal base (about the size of a large ashtray) is referred to as the “after cap”, which was shortened in everyday usage by tankers into “afcap”.
If the 120mm system has a fault, it’s the ammo’s vulnerability to moisture damage (a round composed of chemically treated cardboard will be like that.)
Chobham (correct spelling) Armor was originally developed by the Brits in the late '60s/early '70s. We (the USA) developed our own brand of the stuff (we think that it’s better), but I’ve never heard of it referred to as anything but Chobham Armor. Some that I have known have alluded to some secret alph-numeric designation for the stuff; I was more concerned that it would actually stop the bad guys tank rounds (“Bad Guys”=people shooting at me).
Whether or not the M-1’s armor will stop it’s own 120mm DU Sabot I have no direct personal knowledge or valid scientific studies to cite; I suspect that in a full frontal hit, it will, and have heard anectdotes to that effect from other DS/DS vets.
I know for fact that it will stop a 125mm Sabot from a T-72.
Tracer: no special rounds are used; the HEAT-MP-T round is preferable (High Explosive Anti-Tank, Multi-purpose, tracer), but is a bit slower and less accurate than the DU Sabot round.
Obviously, frontal or acute oblique shots are better, but the sights are gradiated to allow massive amounts of deflection for full-flank shots.
Fixed-wing fast movers are very problematic, but rotary wing attack craft are more vulnerable than they think, at least to the M1 with a well-trained crew.
Sofa King: I followed your link and read most of the article. I say most because I really have no disagreement with the bits that I did read. Essentially, he was saying much the same as I have (or the other way around if you prefer): Armor, in whatever form technology, resources and the tactical environment demand, will never be obsoloete, and new design will have to be adapted to meet changing battleground environments. Nothing new or suprising there.
Light tanks, medium tanks, heavy Main Battle Tanks. Whatever the perceived strategic and tactical environment demand.
Like I said earlier: The M1 family may very well become superfluous; as technology advances, the design itself will certainly become obsoloete.
But the ability to use maneuver and massed firepower from behind the protection of armor to break not only the enemy’s resistance, but also their will to fight, will only become obsolete when war iself is obsolete.
Whether it’s super-infantry in Power Armor ala Heilein, super-tanks ala Drake, Armored Walkers like Battle Tech or Star Wars, or close-support orbital bombardment from space cruisers and such, there’s no such thing as “too much firepower”.
ExTank
“Mostly Harmless :P”
ExTank, I’ve heard several IDF Tankers refer to the armor on the Merkava 3 as “Smart Steel”. Do you think it’s the same as Chobham?
ExTank: Thanks for the explanation. I can see how a slender sabot round might maintain stability while acquiring spin, but I don’t understand how standard rounds like API and HEI would work. Seems like they would be unstable unless they started to spin in the barrel.
When the M1 first came out one of the complaints was that it could not be fitted with a bulldozer attachment like other tanks so it could dig itself in. Something about the transmission not being strong enough. Seems they had to have special combat bulldozers travel with them to dig them in. Did they sort that out in later versions?
Allesan: I doubt that they’re exactly the same, but probably the same principles.
Slipe: The only two types of rounds that we ever dealt with were various Sabot rounds and the HEAT rounds, even though other types were available in the inventory; the original 105mm was a rifled cannon, so special self-spinning rounds weren’t necessary.
But even the relatively massive HEAT-MP-T round has a slender, finned rod behind the warhead to maintain stability.
Herr Bernhard Bals has some good info at Die Panzer Homepage. Click on the American flag for the English version, then scroll down the left-hand menu to the “120mm Ammo” button. Please take the time to sign the man’s guestbook, and leave some feedback.
The “Ammo” descriptions are all in German, but there are some fairly self-explanatory depictions of the rounds, that I’m sure the majority of Dopers can understand.
The M256 was an “off the shelf” system, meaning that it had already been developed and tested, courtesy of the Germans, and required very little modification to be adapted to our use.
Come to think of it, most of the fire-control system, the fire-detection/suppression system, the armor, the suspension and the engine were all “off the shelf” seriously cutting the developmental costs of the M1 family.
As to the “bulldozer/transmission” question, I’ve never heard of any comments concerning the frailty of the transmission system concerning bulldozer duty. Considering the mine-plow attachments never had any detrimental effect on the drive-train, I don’t think so, but this is just IMHO.
I think it has more to do with tanks being used more as maneuver assets, rather than fixed defensive assets. The M901 ITV (Improved TOW Vehicle) was much better suited to positional defense than an M1, and was used thusly in DS/DS.
As far as the Air-Land Doctrine is concerned, it may have been expanded to include more capability from combat-multiplier assests and been renamed; the underlying concept is still there, though. Use everything at once, in a time-coordinated attack to totally overwhelm the enemy with firepower and mobility.
Being Cavalry (I was never Armor!), I’m a bigger proponent of maneuver warfare than positional, though I recognize the necessity of both equally.
Real-Life Story: In my time at Ft. Hood prior to DS/DS, our training revolved around REFORGER, the “REurn of FORces to GERmany”, with the intention being that 1st Cav would leave their vehicles at Ft. Hood, get on an airplane and mate up with pre-positioned equipment in Europe. Thus our training up to that point had been as a pure-Armor role.
Sometime in the second week of August, 1990, it was decided that 1st Cav would deploy with our first-run M1 tanks. We went into accelerated training (which had been cut-back due to budgetary constraints), and we began work-ups on classic Cavalry missions.
One of our officers was complaining that our missions didn’t make any sense; I commented that they were Cavalry missions (having drilled on them rigorously in Germany for two years, I was very familiar with them).
He looked perplexed, and asked, “Why the hell are they giving us cavalry missions?!”
You could’ve heard a pin drop. My platoon sergeant was the only one bold enough to say what we were all thinking: “Gee, Sir, I don’t know; we’re the 1st Battalion, 5th Cavalry Regiment, 1st Cavalry Division. Who knows what the hell those generals are thinking.”
Gotta love those butter-bars :rolleyes:.
ExTank
“Mostly Harmless :p”
So what’s the difference between “Cavalry” and “Armor”? Is it just the difference between offensive and defensive warfare?
I’m sure ExTank can give you the right answer, but in terms of the designations I thought it was mostly a historical one – modern armoured cavalry units were formed from horse cavalry units with a historical pedigree.
In terms of their role, armoured cavalry regiments (ACRs) were intended in Cold War Europe as the “first line” of armour in the event of an invasion, delaying Warsaw Pact tank divisions until the full US, British, Dutch and German armoured units could move into place. As a result they were (IIRC) combined arms units packing a lot of punch and mobility.
In other countries armoured cavalry tends to mean armoured reconnaissance – Britain has no separate armoured reconnaissance regiments, I think (they’re integrated into the tank regiments), and Germany has panzeraufklarungs battalions.
Can you tell I was brought up in an army area?
It should be noted that an ACR is also one of the most air-portable units that we have. It’s not only a defensive unit, it is also the very fiercest conventional projection of power we have, with a respectable nod to the Marines.
Subliminafull.
Cavalry is mostly about composition and mission; the Army has a tendency to leave Cavalry -trained soldiers (even us CDATs) in Cavalry units.
Cavalry is screening and reconnaisance; deployed forward of the main body/fighting force, they will move to make contact with the enemy’s formations, observe their strength, composition and axis of advance, and report the back to the rear.
If necessary, they will engage the enemy in an attempt to delay or divert them, possibly to allow the main body forces to get set for a decisive engagement, or to distract them from a particular area they may be advancing on.
Armor also uses mobility to move rapidly from one tactical area to another, but with more emphasis in toe-to-toe slugging matches with the enemy, or “decisive engagements”
Cavalry will assist by keeping tabs on the enemy, paring down the enemy’s numbers in hit-and-fade engagements, disrupting their formations, disrupting their logistics in behind-the-line raids (one of the main reasons Cavalry units fly the Jolly Roger from an antenna mast), and channeling the enemy onto the ground (terrain) of our choosing, to give our forces the maximum advantage.
I was Cavalry for 6 years, even though I was a tanker, and our unit ran-amok along and behind the neutral zone in Iraq during DS/DS. You’d be amazed at how well you can sneak up on someone with an M-1 tank.
Army FM 17-95 Cavalry Operations details the concept and integrated employment of Cavalry forces, and is a heck of a read (as far as Army FMs go, that is. Actually, it’s boring as hell). I rather recommend Tom Clancy’s Armored Cav for further information on us Horse Soldiers.
ExTank
“Mostly Harmless :p”
How did the British and French armored divisions aquit themselves in the Gulf war? The British have MBT called the CENTURION?-how does it compare to the Abrams tank? Also, did the Frech have their own heavy tank? I understand that after their experience in WWII, the French went for very fast, relatively light tanks-is this doctrine still in effect?
Finally, you described how a depleted uranium AT round from the ABRAMS could pnetrate both front and back of a Soviet T-70 tank-would anybody inside survive this? Or would the fuel/ammo instanly explode?
Horrible way to go!
Thanks, Ex-Tank.
So Cavalry is to Armor what Recon is to Infantry (I know - not precisely, but close enough).
Egkelly: if by some miracle the shell missed both fuel and ammo, it’s still a pretty damn big, fast piece of metal. The richochets would probably kill anyone inside.
Or maybe not - soldiers have been known to survive horrible situations. You never can tell.
IMHO, it certainly looks mean enough. (I’m ex-infantry, and tanks sure scared the crap out of me…)
S. Norman
The Centurions were very old designs. The frontline tank is the Challenger, which I believe is roughly comparable to the M-1. The Challenger II is either being rolled out or due to be rolled out to armoured regiments shortly. Before that, the main '80s tank was the Chieftain.
German tanks (namely the Leopard and Leopard 2) have a reputation for being very reliable, fast and mobile, although not as heavily armed or armoured as US designs. I’ve no idea how the French Leclerc measure up.
Spiny Norman wrote:
They didn’t scare the crap out of Tom Hanks in Saving Private Ryan, though! Why, armed with only a Colt service .45 pistol, he managed to make an entire tank blow up.
(His pistol must have been the cause, because there’s no way a P-51 Mustang during WW2 would have anywhere near enough accuracy to destroy a tank without hurting Tom Hanks standing near it, even when configured for the dive-bomber role. Could you tell I was being sarcastic?)
I never saw any British or French armor over there; not to say they weren’t there, just not in our AO (Area of Operations), and we didn’t stray out of our assigned sectors.
I haven’t heard any American Army or marine Corps tankers dissing the Brits or the French, so I suppose they did alright.
The Challenger is even more heavily armored than the M1-A1 Heavy, and being as they’re diesel powered, they sacrifice mobility for the extra armor protection. They don’t use the Rheinmettal 120mm, but one of their own design and manufacture, but the ammo is still compatible (methinks a bit of economic protectionism was at play there).
As far as the Leos, I think that they are at least equal to the M1 in firepower (the Leo I corresponding to the straight M1, the Leo II and later generations to the M1-A1s), and very closely in mobility. I have heard that they are even more crew-survivable than the M1 series.
The problem with the Leos as I see it isn’t the vehicle; it’s the crews. The German Army was composed largely of conscripts (i’d heard that they had gone to all-volunteer, but haven’t found anything to corroborate this), who usually felt that they had somewhere better to be, so performance suffered.
The German Army regulars (those who enlisted or re-enlisted voluntarily) were as professional as any soldiers I had ever seen; motivated, dedicated, disciplined. Pros.
The Sabot rounds don’t necessarily work by igniting internal combustibles (that’s just a benny of the Soviets crappy tank designs; which, I have been told, were corrected in advanced T-72 and later models).
The sabot round kills the crew with Spalling, that is, armor that is cracked and fragmented. Kind of like a very powerful grenade going off in the turret. An Anti-Spall kevlar lining has been added to the interior walls of the turrets of some models, with the upgrade being considered for the M1-A2.
Cavalry comes in several shapes and sizes; Light Cavalry is motorcycles and dune-buggys; Cavalry now is typically up-armored HUMMERS, mounting .50 cals, Mk-19 automatic grenade launchers and TOW-II missiles.
Armored Cavalry Regiments (like the 3rd, 11th and previously the 2nd, my old unit in Germany) are the heavies; Brigade sized elements with their own artillery and aviation assets (no need to call on someone else and ask), plus a lot of their own logistical assets.
A Regiment is composed of three line squadrons, an aviation squadron and a support (logistics and maintenence support)squadron ( a squadron being roughly equivalent to a battalion).
A line squadron is composed of three cavalry troops (13 M3 Bradleys and 9 M1s each), a tank company (14 tanks) and a howitzer battery (6 M109 series 155mm self-propelled howitzers), for a total of 39 Bradleys, 41 Abrams, 6 Howitzers, plus a 6-tube battery of 120mm mortars, per squadron, for a regimental total of 117 Bradleys, 123 Abrams, 18 Howitzers and 18 120mm mortars. That’s not counting command tracks (tanks and Bradleys, which, theoretically, are combat capable). Then throw in about a dozen Apache gunships with Kiowa scout/forward observers, for tactical flexibility
That’s a heck of an independent force to turn loose to wreak merry havoc behind the enemy’s lines (and yes, it can, and has been, done).
Armored Cav is usually assigned as a Corps asset, and, IMHO, no other unit can move as fast and as far, and kick some serious butt when they get there, than Armored Cav.
Best bang for the buck in the Army’s bag of “nasty things to do to the enemy” tricks.
But I may not be the most objective observer. 
A little ditty I was forced to memorize in basic training can give you a bit of insight into the mind of a Cav Trooper:
The origin and author of Fiddlers’ Green is unkown. It was believed to have originated in the 1800’s and was composed as a song sung by the soldiers of the 6th and 7th Cavalry. Its first known appearance in published form was in a 1923 Cavalry Journal.
ExTank
“Mostly Harmless :p”
ExTank, I have to take exception to something you wrote. I was a conscript, as was everyone I served with, and I believe we could have held our own against anyone you’d care to throw at us. The Israeli tankers who fought in the Sinai and on the Golan Heights were conscripts and reservists, one and all, and you’d be hard pressed to claim they did not prove their worth.
If you want, we could start a separate thread about the difference between conscripts and volunteers. Until then, back off.
The tank was (and is) the Challenger, and it’s quite similar to the Abrams. My understanding, though, is that it is substantially slower moving around. but as near as I can tell that’s its only disadvantage. It uses the same main weapon and, like the Abrams, has some top-secret armor nobody’s supposed to know the composition of called “Chobham” armor.
A very similar NATO tank is the German Leopard-2, though the Leopard-2 apparently has better speed than the Challenger. It’s the general consensus that the M1A1 is the world’s finest tank, but you would not go wrong with Challengers or Leopard 2’s.
The world’s largest tank is actually the Israeli Merkava Mk.4, a lumbering monster of a tank that weighs in well over 70 tons fully loaded out. It’s slower than the NATO heavy hitters, which I always found strange, but I guess the Israelis know a thing or two about tank warfare.
The French do have a main battle tank, the AMX-30. It’s NOT as big as the NATO heavy hitters and packs a smaller weapon, a 105mm (gun the Abrams, Challenger and Leopard 2 all carry the same 120mm gun.) Some AMX-30 models have 20mm guns as well. Despite the smaller size, it’s still not as fast as the top-of-the-line tanks. We’re still talking about a big tank, though. You would not want it to run into your Mazda.
Russian tanks are closer to the French style than the NATO style, choosing smaller models, though with a 125mm gun that can fire AT-11 missiles.
[QUOTE]
Finally, you described how a depleted uranium AT round from the ABRAMS could pnetrate both front and back of a Soviet T-70 tank-would anybody inside survive this? Or would the fuel/ammo instanly explode?
Horrible way to go! /QUOTE]
No, nobody would survive. The tremendous kinetic energy caused by the round’s penetration would spray the internal compartment with red-hot debris. Even if the ammo or fuel miraculously did not explode, the crew would very certainly die.
Allesan: No dis was intended. The conscripts in question I met in 1987; the German Army may have newer incentives to improve performance.
I never said that they were worthless dirtbags, either. Just not as motivated as the regular troops. I’m sure that there were exceptions (there always are, in broad genaralizations). I was merely speaking of my personal experiences in my admittedly limited contact with the forces of foreign armies.
Besides, the Israeli’s have a whole different mind-set and approach (not to mention one hell of a lot of external motivation) to Being All They Can Be.
Hey, I ran into a group of Brits and Aussies doing joint-training at Grafenwohr. They were all jolly good blokes until the beer started flowing, and then they started raking up stuff that only Aussies and Brits understand and throwing it back and forth at one another until the fists flew and the MPs had to break things up.
Does this mean that all Brit and Aussie soldiers are okay until alcohol is added? Probably not, but it does make one hell of a first (and only) impression.
Same thing with the Greek and Turk soldiers; okay individually, but does not mix well.
ExTank
“Mostly Harmless :p”