Assault Gun v. Tank Hunter/Destroyer--Tech Diff?

[Commissar]

What is the technical difference in actual design between the assault gun and tank hunter/destroyer? I understand the philosophy and combat roles but I am wondering about the technical if not formal difference. Both seem to be turretless but obviously there must be something else.

Also, why have these kinds of vehicles disappeared? Have modern infantry combat vehicles like the BMP and M2 taken over this role? No longer really necessary with modern MBTs?

[Sergei]

I think assault gun is what Germans called StuG's (Sturm Gewehr). The first versions were equipped with a low velocity 75mm (L24? ), the same which was in PzKpfw IVd's. And that was intended to be used against enemy infantry. Later versions had a higher velocity gun which was useful against tanks as well.

Tank destroyers and panzer jägers were explicitly designed to destroy tanks. You might notice that U.S. tank destroyers actually had rotating turrets. On the other hand, there were also tanks such as Char B or M3 Grant/Lee, in which there was a howitzer put into hull, with a smaller calibre AT gun in turret.

I really don't know why they disappeared, but I guess the turretlessness (eh...) was just a way to reduce cost.

[Jeff Heidman]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Commissar:

What is the technical difference in actual design between the assault gun and tank hunter/destroyer? I understand the philosophy and combat roles but I am wondering about the technical if not formal difference. Both seem to be turretless but obviously there must be something else.

<HR></BLOCKQUOTE>

The theoretical difference would be that an assault gun would not have a high velocity cannon, since its primary duty was to engage soft targets. A TD would have the best performing AT gun possible for its cost/size.

In reality, the assault guns ended up with decent AT guns anyway. In the case of the German AG/TDs, the AG ended up with the 75L40, which was a good AT gun, but no better. The TDs got anything from the 75L40 at the low end, up to the various types of 88mm guns at the higher end.

<BLOCKQUOTE>quote:</font><HR>

Also, why have these kinds of vehicles disappeared? Have modern infantry combat vehicles like the BMP and M2 taken over this role? No longer really necessary with modern MBTs?<HR></BLOCKQUOTE>

There are two ways to look at this:

1. The advent of the ATGM makes the preferred "cheap" AT weapon the IFV or another dedicated "light" ATGM platform (ITV, and such). So you could say that the ATGM has taken over the primary role of the TD.

2. The MBT as we know it today is the TD of WW2. Current tanks are designed to engage and defeat enemy armor as their primary mission. For example, the US Army M1 Abrams no longer has an HE round for its main gun. I think they are supposed to use harsh language if they run into enemy infantry.

Jeff Heidman

[Schwarze]

Sturm Ghewer means Assault Rifle

its SturmgeSchutz (German for Assault gun)

[ 06-11-2001: Message edited by: Schutzstaffel ]

[offtaskagain]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jeff Heidman:

2. The MBT as we know it today is the TD of WW2. Current tanks are designed to engage and defeat enemy armor as their primary mission. For example, the US Army M1 Abrams no longer has an HE round for its main gun. I think they are supposed to use harsh language if they run into enemy infantry.

Jeff Heidman<HR></BLOCKQUOTE>

I think that 120mm HEAT round they carry packs enough blast to cause problems for infantry. I know it's definitely good for busting bunkers. Otherwise they are kinda useless against infantry. Rather like early Fireflys.

[ParaBellum]

Assault guns were introduced to give the infantry direct fire support. In the mid 30's there were a lot of discussions in the german army about the use of tanks and their influence on tactics.

The artillery branch saw the StuGs as a means to "recapture" some lost ground from the tanks and their leading advocate Guderian. He was against the StuGs since he felt that a turreted tank was a much more potent weapon than the turretless StuGs and he felt that the StuGs based on the hulls of the Pz III and IV would hamper the tank production.

During the course of the war the priority for the StuGs slowly shifted from an infantry support role to an anti-tank role.

Their low profile and good armour made them quite good tank destroyers although their designation still pointed to their role as support tanks for the infantry.

The first tank hunters like the Marder were rushed into production to overcome the threat caused by the russian T-34s and KV series. They were lightly armoured and were more a mobile AT gun than a tank. Their vulnerability showed the need for well armoured tank destroyers that led to the Jagdpanzer IV, the Hetzer and finally the Jagdpanther.

The most important features for a tank destroyer are armour and a high velocity gun since he will engage enemy tanks as his primary target. IMO the design of the StuGs could also be called a "tank destroyer" according to these specifications.

Today there are still tank destroyers. They've traded their high velocity guns for AT missiles. These vehicles are fast, lightly armoured and (most important) cheaper than an MBT.

[PzKpfw 1]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jeff Heidman:

2. The MBT as we know it today is the TD of WW2. Current tanks are designed to engage and defeat enemy armor as their primary mission. For example, the US Army M1 Abrams no longer has an HE round for its main gun. I think they are supposed to use harsh language if they run into enemy infantry.

Jeff Heidman<HR></BLOCKQUOTE>

They are to use their MGs to supress Inf now as well call in arty on the Inf engageing them .

HEAT-MP is about useless vs inf due to small AP capability. The US Army back in 96 did put a contract out for an new 120mm AP (Anti Personel) round, but i have heard nothing since on the progress.

Regards, John Waters

[Sten]

There are several pictures on the internet of my favourite Swedish tank (really, a tank hunter), the "Stridsvagn 103 S".

Some pictures: http://www.ifrance.com/ArmyReco/europe/Suede/vehicules_lourds/CharS/Stridsvagn_103_suede_diaporama.htm

More pics and some info: http://home5.swipnet.se/~w-58324/strv.htm

These links are just examples. There are several more.

Sadly, the Stridsvagn S was discontinued about 2 years ago. But as you can see from the pictures the Swedish army retained the "Tank hunter" look in to the new millenium. There's a low profile for you.

3 man crew (commander, driver/gunner and radio opperator/rear driver), 105 riled main gun.

One driver drives it to a decent ambush position, waits, fires, and then the other driver gets it the h*ll out. Neat, huh?

[Enoch]

I've always had some question about the development of turretless armored vehicles.

First of all, why no turret? Cheaper? Uses less resources? Infantry support doesn't require a turret? I can't see any obvious advantage to having no turret over having one.

[Jeff Heidman]

<BLOCKQUOTE>quote:</font><HR>Originally posted by PzKpfw 1:

They are to use their MGs to supress Inf now as well call in arty on the Inf engageing them .

HEAT-MP is about useless vs inf due to small AP capability. The US Army back in 96 did put a contract out for an new 120mm AP (Anti Personel) round, but i have heard nothing since on the progress.

Regards, John Waters<HR></BLOCKQUOTE>

The MG concept is just a "pat" asnwer for tankers when they ask what they should do when presented with infantry. Essentially, an M1 Abrams has less ability to deal with enemy infantry than a PzIII. Conversely, infantry has a much greater ability to deal with an M1 Abrams than any poor Polish soldier had of dealing with that PzIII. How are you going to supress infantry at more than 1000 yards with a MG? A man portable ATGM can reach out and touch an MBT at 2 klicks, or more.

I think the real reason (and maybe its even a good one) is money. Given the Armies fascination with killing tanks, they have elected to spend their dollars on procuring better and better AT ammo (very expensive in terms of research and procurement), and probably figure that if a real war breaks out, it would be pretty quick and easy to throw together a 120mm HE round.

Jeff Heidman

[ 06-11-2001: Message edited by: Jeff Heidman ]

[offtaskagain]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jeff Heidman:

How are you going to supress infantry at more than 1000 yards with a MG? A man portable ATGM can reach out and touch an MBT at 2 klicks, or more.

Berkut<HR></BLOCKQUOTE>

There aren't a whole lot of ATGMs that can bother an M1 though. A TOW-2B, Hellfire or Javelin can, but who has those ? . If you wanna argue, how many M1s were killed in Iraq?

[ 06-11-2001: Message edited by: panzerwerfer42 ]

[PzKpfw 1]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Jeff Heidman:

I think the real reason (and maybe its even a good one) is money. Given the Armies fascination with killing tanks, they have elected to spend their dollars on procuring better and better AT ammo (very expensive in terms of research and procurement), and probably figure that if a real war breaks out, it would be pretty quick and easy to throw together a 120mm HE round.

Berkut<HR></BLOCKQUOTE>

Well the Army's fascination with killing tanks stems from the cold war. When tanks were an major threat in a NATO/PACT confrontation. That time has passed & Nations are now looking to replace their HA with lighter more economical vehichles.

As to engageing Inf the co-axe on the M1A2 using the FCS can engage at 800 - 1000ms from what we were told during SP2 development.

When we brought up the question of tactics vs Inf ATGMs I was told the SOP was to pop smoke & call in Arty, this was from an Armor Col who fought in the Gulf.

They did award a contract in 95-96 to an company to make an 120mm HE round, I just never heard what became of the round, its probably moot now with the comeing changes in the armor forces.

Regards, John Waters

[Jeff Heidman]

<BLOCKQUOTE>quote:</font><HR>Originally posted by panzerwerfer42:

There aren't a whole lot of ATGMs that can bother an M1 though. A TOW-2B, Hellfire or Javelin can, but who has those ? . If you wanna argue, how many M1s were killed in Iraq?

[ 06-11-2001: Message edited by: panzerwerfer42 ]<HR></BLOCKQUOTE>

Not frontally; there are plenty that can "bother" them to the side or rear.

And lets not use the Gulf War as a testing ground. Actually, I take that back; the Gulf War was an excellent "testing ground", but not much of an indicator of what is going to happen if the US goes up against a determined opponent somewhere other than the middle of a desert.

Jeff Heidman

[JasonC]

"why no turret?"

They are cheaper, yes. But in addition, the same chassis can carry a heavier gun without a turret than with one. That is the primary motivation. The vehicle also becomes shorter, making it harder to spot or hit, but that is more of a welcome side effect, rather than the motive.

A turret takes up weight and is limited in its size by the overall dimensions of the vehicle. For the largest guns, you also have to worry about the recoil when firing sideways. Heavier guns in turrets require counterweights at the rear to allow the turret to turn smoothly about its centerpoint, as the long barrel creates a long "moment arm" for angular momentum. The bigger the gun, the bigger the difference in overall weight for a turreted vs. an unturreted version.

In WW II, the StuG III used the chassis of the Pz III. It carried at 75L48 gun, and some versions used a 105mm howitzer. The best guns that would fit in the largest turret the chassis could handle, were 50mmL60 and a short 75mmL24.

The Pz IV chassis fit a 75L48 gun in a turret. Turretless versions of the same chassis carried 75L70 (Jadgpanzer-70), 88L71 (Nashorn), and 150mm howitzer (Hummel).

The Czech chassis, in tank form, carried a 37mm gun in a turret. Turretless versions carried 75L48 (Marder and Hetzer). The Pz II carried only a 20mm gun in a turret. But the chassis could handle a 75L48 (Marder) or 105mm howitzer (Wespe) in turretless form.

The difference is obviously most dramatic with the smaller chassis. With big ones, the increase is still there, but less important - Panther going from 75L70 to 88L71 as the Jadgpanther, or King Tiger going from 88L71 to 128mm as the Jadgtiger. All of them already capable, making the increase a bit of overkill for most purposes.

During the war, the chassis are already there. They are being made in large numbers. It is not a matter of designing a new vehicle from the ground up, which would be much more expensive and above all, take much longer. When an older and lighter chassis can no longer carry a powerful enough gun to be useful against typical enemy armor, it is natural to upgrade the gun and keep using the chassis.

On the Russian side, the T-70 light tank used a 45mm gun in a turret. Turretless, it carried a 76mm gun - the SU-76. The T-34 originally carried a 76mm gun. TD versions carried 85mm and 100mm AT guns, or the 122mm howitzer. The heavier KV had the same initial gun in a turret, but could carry 152mm howitzer as a TD. The IS series started with an 85mm gun and then upgraded it to 122mm. TD versions carried 122mm or 152mm long-barrelled gun-howitzers.

The Russians were essentially copying the Germans moves - they dropped their light tanks for SU-76 right after the Germans dropped theirs for Marders. They saw the Germans using StuG to support infantry with howitzer direct fire, so they made the SU-122.

The western Allies used turreted TDs, but sacrificed weight of armor on the turret and turret tops to get weight and room. The Sherman chassis could take a 90mm gun that way. Initially in North Africa, US TDs were based on lightly armor SPAT designs, on halftracks and such. Some dismounted AT guns were tried instead, for better concealment. But the Sherman chassis based TDs proved more effective than either.

Why did the sacrifice of a turret to get a better gun, seem worth it? When the old gun became obsolete for one. When on defense and firing from ambush for another. When staying entirely within one's own infantry lines and frontally bombarding enemy strongpoints, for a third.

Turrets were considered essential for the role of true tanks, which was to attack and penetrate the enemy defensive zone, bypassing points of resistence. Bypassing means enemies left behind one's position. Maneuvering through the enemy defended zone means enemies on either side, or all sides.

Now, assault guns did not bypass resistence, they parked opposite it and shot it up until gone. TDs did not plunge into the middle of the enemy position, they fired "keyhole" when possible from range or from ambush, and on defense.

In practice, the turretless AFVs were often pressed into roles more suited to tanks, and the lack of a turret was certainly a weakness in that case. But better that weakness, than the much more debilitating one of an ineffective gun, or not having an AFV at all. And when used in their intended roles, the lack of a turret was only a minor drawback, while a more powerful gun was an enourmous benefit.

[Andrew H.]

Of course, using HE against 2-man ATGM teams is not the most effective way of dealing with infantry either; see, e.g., the Ferdinand. I'm not exactly sure what you do in non-tank country, but I don't think that HE is the answer.

[Jeff Heidman]

<BLOCKQUOTE>quote:</font><HR>Originally posted by Andrew Hedges:

Of course, using HE against 2-man ATGM teams is not the most effective way of dealing with infantry either; see, e.g., the Ferdinand. I'm not exactly sure what you do in non-tank country, but I don't think that HE is the answer.<HR></BLOCKQUOTE>

As one of those 2-man ATGM team members (actually 3 for the TOW-2), I can assure you that the thought that a T-72 could spot my fire and have 2, maybe 3 rounds of 120mm HE close to me before my missile reached him was defintely of great concern!

Jeff Heidman

[ 06-11-2001: Message edited by: Jeff Heidman ]

[Enoch]

Thanks Jason, most informative and pretty much answers my questions.

[Skipper]

Btw, standard loadout of modern russian tanks packs quite a few HE rounds, with much bigger 'blast value' than M1's HEAT.

[CombinedArms]

Getting back to the original question about the difference between TD's & assault guns, one reason it all might seem confusing is that the defining FEATURES of the AFVs seem to contradict and overlap. E.g. Assault guns never have turrets, but many TDs don't have turrets and even some tanks didn't. Assault guns were used frequently in tank roles and also in TD roles. Etc., etc.

I think maybe the best way to understand it all is to notice that the name goes with the original, intended purpose of the AFV. If it's meant to be a tank, it's called a tank. If it's meant to destroy tanks, it's called a TD. If it's meant to provide HE firepower for infantry assaults, it's called an assault gun. Features may vary; how it was used in practice may vary. But the name is always consistent with its original intended use.