A question on tank rounds
 

A puzzling question for me is, why did the Russian make a gun launched anti-tank missile? To me that is just dumb when you have access to a 125 mm gun! Is this to make up for a lack of power in it's SABOT? Or a lack of good future target positioning electronics for their main gun? I could see something in the anti-air catagory for this, but anti-tank?

-S

We had the same thing in our inventory at one time:

http://en.wikipedia.org/wiki/MGM-51_Shillelagh

1. The US had a muzzle-launched ATGM as well, in the 1960s
2. Range. A Sabot round loses energy pretty quick due to air resistance. A shaped charge is equally effective at all ranges. And the most accurate way to deliver such a charge is a missile. I suppose the idea is to engage NATO tanks at ranges where their Sabot rounds are not effective against the tank's armour.

I'm just guessing, but perhaps it could be fired with out a direct line of fire/visual contact.

A shaped charge has more penetration against old armor types too.

That's old stuff though. No longer needed when you have a tank sight that can put a round down range a couple miles out to hit a target at an exact point in space and time.

-S

There is an idea, but if you have boots on the ground to see it, that carry AT missiles anyway, and if its from the air, they also carry AT missiles (Every squad packs one in Iraq - though they always use them on buildings lately). Tanks are for direct combat.

Top attack is nice, but not much stops a SABOT.

This is why I am puzzled why it exists?

-S

Who knows? Maybe the Russians perfected the technology.

Oh, I dunno, I would expect non-penetrating sabot rounds are more common
than non-penetrating shaped charge rounds against conventional armor. Right?

I'd venture to say you've got it backwards. The very reason HEAT rounds are no longer used for tank to tank fighting, at least from a US perspective.

-S

As evidenced by the performance of U.S. and British tanks during GW1, American tanks were able to knock out Iraqi T-72's that were hiding behind sand berms, while British tanks were able to knock them out from even longer ranges using HEAT, provided they were in the open.

Yes, HEAT is more effective at lower impact velocities (ie, super long range), but APFSDS takes the cake when an enemy is in cover or is shooting back, whicj is most of the time when one fights a developed nation.

I'd go with APFSDS rounds.

Well yeah, these thoughts are true as well since the HEAT rd will be having a higher trajectory, but if I had to choose one or the other, give me a good SABOT any day! Only in the desert does combat frequently happen at those ranges. Though American tanks carry a store of both types. M1A2's carry 42 rds in all.

-S

Main drawback behind the APFSDS is that since it is a kinetic energy weapon, its penetration will drop over distance. OTOH at the velocities that they travel at, trajectory is very much flatter than a HEAT round. It's effectiveness will depend also on the gun firing it.

Main advantage behind the HEAT is that penetration doesn't depend on distance. Also in a pinch they can be used as an anti-material warhead (say taking out a building) which the sabot round isn't good at.

As to why the Russians use tank-fired ATGMs, I have no idea, sorry.

I would also wager that a HEAT round is cheaper and easier to manufacture than a APFSDS round. Maybe that influences the decisions.

Other influences may include

If APFSDS rounds are fired from rifled barrels, it causes more wear in the barrel. This is due to the need for a "de-rotating" sabot to keep the kinetic core from spinning. A spinning APFSDS round won't travel as far and will have decreased accuracy. This is one of the reasons APFSDS rounds are usually fired from smooth bore barrels. The advantage of HEAT rounds is that it can be carried with other tank rounds that need rifled barrels.

The core of a APFSDS round is expensive and difficult to manufacture. Working with either Depleted Uranium or Tungsten Staballoy is not was easy as manufacturing a HEAT round.

There is an ongoing debate concerning the use of DU rounds.

Although this is probably not a big concern to the big brass, but it must suck being Infantry and having your forces firing APFSDS rounds from behind you. Them sabots have to end up somewhere. The Sabots, upon separating from the core, will continue down range a few hundred meters. Bouncing off the helmets of the Infantry guys in front of you. Ouch.

Lesson 1: Don't be in front of a tank firing APFSDS rounds :know:

Both rounds (APFSDS and HEAT) have their advantages and disadvantages. I don't think one is clearly always better than the other in all situations.

Now if you want to talk about HEP rounds (or HESH to your Brits)... That's innovative technology :up:

I think the missiles are to compensate the bad accuracy of the gun and sights on longer ranges.

Actually, the Soviets, for many years, didn't really worry all that much about their sabot. In the 1960s and 70s, NATO armor is basically steel, and not all that thick (with the exception of Chieftain, and even that's steel), so either HEAT or sabot rounds mostly made of steel (plus a dib of tungsten, as opposed to the tungsten or DU designs today) were most adequate.

Also, in the 1970s, fire control wasn't as advanced as it is today. Besides, even a theoretically perfect FCS starts to have trouble when the flight time of the round exceeds one second, thus the target has an opportunity to deliberately or accidentally alter its vector. Especially if it is a helicopter. Unless, of course, the round is guided, so you can correct your own round's flight.