35 replies to this topic

[TOW-2]

So the 90mm gun M-1 was used in various forms by the US military (and others) as an anti-tank gun, coastal defense artillery, main gun for tanks and anti-aircraft.  Was the only relation between these systems the caliber of the gun?  I mean obviously a tank isn't going to carry proximity fused anti-air rounds nor is an AA battery going to be armed with HVAP (probably?) but I wonder how much DNA they all share.  I mean, the M48 was armed with the M54 variant, but, again, was it purely the caliber of the gun?

 

Likewise did the development of large caliber AA guns by the Soviets inform their tank gun designs?  I believe they had what, up to 140mm AA guns?  Were any adapted to tank use or were the guns derived from extant tank and artillery pieces initially used solely against land targets (or even naval weapons at that caliber).

 

Thanks in advance!

[Rich]

"It is also important to understand that the 90mm M1 AA Gun and the 90mm M3 Tank Gun were not the same weapons. They did utilize the same basic chamber and tube assembly, but there were significant differences in the design and manufacture of the mounting, breech, gun tube, firing mechanism, and fire control equipment. A new breech ring was designed that could mate with the piston rods of the recoil mechanism of the 3” Gun, while new sleeves with increased resistance to absorb the greater recoil of the 90mm were fitted to the piston rods. The breech operating handle was moved directly onto the breech mechanism. The breech operating cam was modified to operate the breech semi-automatically. Finally, a longitudinal key-way and a cylindrical recoil surface were added to the exterior of the gun tube itself, which permitted it to fit the 3” Mount, M7 in the GMC M10. That necessitated decreasing the exterior diameter of the gun tube.  Ordnance developed the 90mm M3 Tank Gun specifically because of problems encountered and deficiencies noted in early attempts to fit the 90mm AA gun into a tank or self-propelled chassis." (from my ms.)

[TOW-2]

"It is also important to understand that the 90mm M1 AA Gun and the 90mm M3 Tank Gun were not the same weapons. They did utilize the same basic chamber and tube assembly, but there were significant differences in the design and manufacture of the mounting, breech, gun tube, firing mechanism, and fire control equipment. A new breech ring was designed that could mate with the piston rods of the recoil mechanism of the 3” Gun, while new sleeves with increased resistance to absorb the greater recoil of the 90mm were fitted to the piston rods. The breech operating handle was moved directly onto the breech mechanism. The breech operating cam was modified to operate the breech semi-automatically. Finally, a longitudinal key-way and a cylindrical recoil surface were added to the exterior of the gun tube itself, which permitted it to fit the 3” Mount, M7 in the GMC M10. That necessitated decreasing the exterior diameter of the gun tube.  Ordnance developed the 90mm M3 Tank Gun specifically because of problems encountered and deficiencies noted in early attempts to fit the 90mm AA gun into a tank or self-propelled chassis." (from my ms.)

 

Thank you so much!  That's exactly the kind of insight I'm seeking.  

 

-Bill S.

[bojan]

As usual when someone says "they put AA gun into turret of the tank" he is talking BS. At best, gun will share a barrel, but most often not even that*, only chambering and basic ballistic will be same.

 

Soviet 85mm family - 85mm 52K AA-gun had L/55.2 barrel, D-5S/D-5T guns had L/51.6 and S-53/ZiS-S-53 had L/54.6 barrel length. Post war 85mm D-44 field gun was L/55.1... None of those shared barrel.

[TOW-2]

As usual when someone says "they put AA gun into turret of the tank" he is talking BS. At best, gun will share a barrel, but most often not even that*, only chambering and basic ballistic will be same.

 

Soviet 85mm family - 85mm 52K AA-gun had L/55.2 barrel, D-5S/D-5T guns had L/51.6 and S-53/ZiS-S-53 had L/54.6 barrel length. Post war 85mm D-44 field gun was L/55.1... None of those shared barrel.

 

That's what I'm rapidly coming to understand.  Thank you, too, Bojan.

[shep854]

Because they are high velocity by design, AA guns made great starters for tank guns. Consider how FLAK 88s were frequently pressed into service as AT guns; fearsome ones at that.

Edited by shep854, 11 February 2018 - 2243 PM.

[bojan]

Yes, but AA guns were minority of basis for WW2 tank guns:

 

 

Let's look at US ones:

37mm - based on AT gun

75mm M2/M3 - based on 75mm field gun

76mm M1 - 3" AT/SP gun ballistics, but completely new construction, not even sharing ammo with 3". 3" was based on 3" AA gun ballistics, which was based on 3" coastal gun.

90mm M3 - 90mm AA gun ballistics and shared ammo to a degree.

90mm M36/M47etc - improved 90mm M3

 

 

Germans:

3.7cm - based on AT gun ballistics, but different construction

5cm, short - original development

5cm, long - based on AT gun ballistics, but different construction

7.5cm kwk 37 - original development

7.5cm kwk 40 - based on AT gun ballistics, but different construction

7.5cm kwk 43 - original development

8.8cm kwk 36 - based on AA gun ballistics, but different construction

8.8cm kwn 43 - inspired by AA gun ballistics, but fully original construction not even sharing ammo with AA gun

 

Soviet:

45mm - based on AT gun. Actually used some of the same mechanisms of it and shared a barrel

76mm KT-28 - based on 76mm model 1927 regimental gun, shared a lot of the construction and ammo

76mm L-10 - actually based on 76mm model 1915 AA gun, but used also parts from KT-28. Used standard field gun ammo, unlike KT-28 which used regimental gun ammo.

76mm L-11 - improved (longer barrel) L-10

76mm F-32 - same ballistics as L-11, new original construction

76mm F-34/ZiS-5 - improved F-32 with longer barrel, to match 76mm field guns ballistics

85mm D-5T - 85mm AA gun ammo and ballistics, new construction

85mm S-53/ZiS-S-53 - new construction, same ammo and ballistics as D-5

100mm D-10S/D-10T - based on ballistics of naval AA gun, but gun was fully a new construction

122mm D-2-5/D-25 - based on 122mm A-19 field gun, but new construction

 

British

2/6/17pdr -  based on AT guns

75mm - based on 6pdr with a new barrel, same ballistics as US 75mm M3

20pdr - original construction

 

Post war US 120mm AA gun was a starting point regarding ballistics that led to a both US 120mm M58 and UK 120mm L1, but nothing more.

 

In case of post WW2 Soviets, there was a reverse experience - experimental 130mm tank gun actually led to a AA gun...

Edited by bojan, 11 February 2018 - 2320 PM.

[TOW-2]

 

In case of post WW2 Soviets, there was a reverse experience - experimental 130mm tank gun actually led to a AA gun...

 

THAT is the one I was thinking of (in the case of Soviet designs).

Edited by TOW-2, 12 February 2018 - 0102 AM.

[DougRichards]

Meanwhile, the other way around in many ways: The M24 Chaffee used a gun derived, not from an AA gun, but from an aircraft mounted 75mm gun - the

 

A new lightweight 75 mm gun was developed, a derivative of the gun used in the B-25H Mitchell bomber.  The gun had the same ballistics as the 75 mm M3 in use by American tanks but used a thinly walled barrel and different recoil mechanism.

 

ie

 

T13E1 / M5

A lightweight version of the M3 with a lighter thin-walled barrel and a different recoil mechanism that was used in the B-25H Mitchell bomber. It uses the same ammunition and has the same ballistics as the M3.

[DKTanker]

Meanwhile, the other way around in many ways: The M24 Chaffee used a gun derived, not from an AA gun, but from an aircraft mounted 75mm gun - the

 

Which was part of the family M2, M3, M4, M5, M6 all derived from the 1897 French 75mm.  The M2 was significantly different because its barrel length was shortened to 31 calibers whereas the rest were 36 calibers.  However, all of the guns were chambered the same and could fire the same family of rounds.

The significant difference of the M5 and M6 from its older siblings is that they utilized concentric recoil systems, a type of recoil system which would become a popular feature in subsequent US tanks.

Edited by DKTanker, 12 February 2018 - 0345 AM.

[shep854]

Thanks for the breakdown, Bojan.  From the original post, I was mainly thinking of the 90mm, 88mm and 85mm guns; it seemed to me that the most powerful WWII tank guns were of AA origin.  I had also thought the Brits modified an AA gun somewhere...glad to learn!

[Rich]

Which was part of the family M2, M3, M4, M5, M6 all derived from the 1897 French 75mm.  The M2 was significantly different because its barrel length was shortened to 31 calibers whereas the rest were 36 calibers.  However, all of the guns were chambered the same and could fire the same family of rounds.

 

 

The significant difference of the M5 and M6 from its older siblings is that they utilized concentric recoil systems, a type of recoil system which would become a popular feature in subsequent US tanks.

 

 

To be clear, the M2, M3, M4, M5, and M6 75mm Guns all derived from the "French 75mm" cartridge and projectile, not from the gun, the M1897/M1897A2/M1897A4. The 75mm Gun M2 derived from the 75mm AA Gun T6, which was a failed Ordnance design for an "all-purpose" AA and Field gun in a program that began c. 1933 as the T2/T2E1 75mm Gun and Carriage.

Edited by Rich, 12 February 2018 - 1201 PM.

[DKTanker]

To be clear, the M2, M3, M4, M5, and M6 75mm Guns all derived from the "French 75mm" cartridge and projectile, not from the gun, the M1897/M1897A2/M1897A4. The 75mm Gun M2 derived from the 75mm AA Gun T6, which was a failed Ordnance design for an "all-purpose" AA and Field gun in a program that began c. 1933 as the T2/T2E1 75mm Gun and Carriage.

 

It all gets a bit confusing sometimes, doesn't it?  Is the M68 a derivative of the L7, or is the M68 just another 105mm gun which can fire the same family of NATO 105mm cannon rounds?  Still, people, intelligent people, are known to substitute one nomenclature for other.  Why not?  They fire the same ammunition from the same size and bore length gun*.  On the other hand nobody, not even the must dull, would ever confuse the M73 with the M240/MAG 58, with the G3, with the M60.  All of them fire the same family of NATO 7.62x51 from the same interchangeable disintegrating link but not one of them is anything like the other.  

 

*I am aware that nothing, save for the number of bore evacuator holes, of the M68 is interchangeable with the L7.

Edited by DKTanker, 12 February 2018 - 1245 PM.

[Old ROF]

 

To be clear, the M2, M3, M4, M5, and M6 75mm Guns all derived from the "French 75mm" cartridge and projectile, not from the gun, the M1897/M1897A2/M1897A4. The 75mm Gun M2 derived from the 75mm AA Gun T6, which was a failed Ordnance design for an "all-purpose" AA and Field gun in a program that began c. 1933 as the T2/T2E1 75mm Gun and Carriage.

 

It all gets a bit confusing sometimes, doesn't it?  Is the M68 a derivative of the L7, or is the M68 just another 105mm gun which can fire the same family of NATO 105mm cannon rounds?  Still, people, intelligent people, are known to substitute one nomenclature for other.  Why not?  They fire the same ammunition from the same size and bore length gun*.  On the other hand nobody, not even the must dull, would ever confuse the M73 with the M240/MAG 58, with the G3, with the M60.  All of them fire the same family of NATO 7.62x51 from the same interchangeable disintegrating link but not one of them is anything like the other.  

 

*I am aware that nothing, save for the number of bore evacuator holes, of the M68 is interchangeable with the L7.

 

 

In theory the early barrel of both the L7 and M68 ordnance variants were interchangeable. Although the UK breech was horizontally aligned and the US breech was vertical, the breech interfaces to the barrel/tube (Start of thread position, extractor pockets, etc on the barrel end) were the same. This was why there were additional machined elements on the Fume Extractor / Bore Evacuator barrel interface which enabled the off-set / eccentrically mounted cylinder to be located with the correct orientation.

 

Changes in the manufacturing methods and hence tolerance systems used between the UK and US over the years, and the incorporation of muzzle upstands which 'handed' the barrel orientation meant this was no longer possible.

[Rich]

 

To be clear, the M2, M3, M4, M5, and M6 75mm Guns all derived from the "French 75mm" cartridge and projectile, not from the gun, the M1897/M1897A2/M1897A4. The 75mm Gun M2 derived from the 75mm AA Gun T6, which was a failed Ordnance design for an "all-purpose" AA and Field gun in a program that began c. 1933 as the T2/T2E1 75mm Gun and Carriage.

 

It all gets a bit confusing sometimes, doesn't it?  Is the M68 a derivative of the L7, or is the M68 just another 105mm gun which can fire the same family of NATO 105mm cannon rounds?  Still, people, intelligent people, are known to substitute one nomenclature for other.  Why not?  They fire the same ammunition from the same size and bore length gun*.  On the other hand nobody, not even the must dull, would ever confuse the M73 with the M240/MAG 58, with the G3, with the M60.  All of them fire the same family of NATO 7.62x51 from the same interchangeable disintegrating link but not one of them is anything like the other.  

 

*I am aware that nothing, save for the number of bore evacuator holes, of the M68 is interchangeable with the L7.

 

 

Yep, in spades when it's U.S. Army Ordnance doing the nomenclaturing. Like, just exactly what was the 75mm M1 Gun?

[Old ROF]

Yes, but AA guns were minority of basis for WW2 tank guns:

 

 

Let's look at US ones:

 

Germans:

 

Soviet:

 

British

2/6/17pdr -  based on AT guns

75mm - based on 6pdr with a new barrel, same ballistics as US 75mm M3

20pdr - original construction

 

Post war US 120mm AA gun was a starting point regarding ballistics that led to a both US 120mm M58 and UK 120mm L1, but nothing more.

 

In case of post WW2 Soviets, there was a reverse experience - experimental 130mm tank gun actually led to a AA gun...

 

Just for completeness, there was one additional British ordnance developed that can be included in the lists..     

The 3.7" AA ordnance was used towards the end of the war as the basis for the 32 pounder (94mm) ordnance of the experimental Tortoise anti-tank vehicle. (https://en.wikipedia...e_QF_32-pounder).

[DKTanker]

In theory the early barrel of both the L7 and M68 ordnance variants were interchangeable. Although the UK breech was horizontally aligned and the US breech was vertical, the breech interfaces to the barrel/tube (Start of thread position, extractor pockets, etc on the barrel end) were the same. This was why there were additional machined elements on the Fume Extractor / Bore Evacuator barrel interface which enabled the off-set / eccentrically mounted cylinder to be located with the correct orientation.

 

 

There is a lot more than merely the orientation of the breech that was different.  Yes, the M68 breech oriented in the vertical plane, but it is also round.  But beyond shape, there is the the necessity of the gun tube itself to act as the piston of the recoil system.  Whereas the L7 utilized external recoil cylinders and return springs, the M68 uses a concentric recoil cylinder.  So you see even if the breech threads are the same pitch and number, and even if the retaining pin and plug are the same (they may well be), there is no way an L7 Tube will work in an M68s mount because it isn't machined to act as a piston.

[TOW-2]

 

To be clear, the M2, M3, M4, M5, and M6 75mm Guns all derived from the "French 75mm" cartridge and projectile, not from the gun, the M1897/M1897A2/M1897A4. The 75mm Gun M2 derived from the 75mm AA Gun T6, which was a failed Ordnance design for an "all-purpose" AA and Field gun in a program that began c. 1933 as the T2/T2E1 75mm Gun and Carriage.

 

It all gets a bit confusing sometimes, doesn't it?  Is the M68 a derivative of the L7, or is the M68 just another 105mm gun which can fire the same family of NATO 105mm cannon rounds?  Still, people, intelligent people, are known to substitute one nomenclature for other.  Why not?  They fire the same ammunition from the same size and bore length gun*.  On the other hand nobody, not even the must dull, would ever confuse the M73 with the M240/MAG 58, with the G3, with the M60.  All of them fire the same family of NATO 7.62x51 from the same interchangeable disintegrating link but not one of them is anything like the other.  

 

*I am aware that nothing, save for the number of bore evacuator holes, of the M68 is interchangeable with the L7.

 

 

I have frequently seen the M68 written out as "M68/L7", so at least a few authors I've read seem to think they're the SDG.*

 

 

*=same damn gun  

[Old ROF]

 

In theory the early barrel of both the L7 and M68 ordnance variants were interchangeable. Although the UK breech was horizontally aligned and the US breech was vertical, the breech interfaces to the barrel/tube (Start of thread position, extractor pockets, etc on the barrel end) were the same. This was why there were additional machined elements on the Fume Extractor / Bore Evacuator barrel interface which enabled the off-set / eccentrically mounted cylinder to be located with the correct orientation.

 

 

There is a lot more than merely the orientation of the breech that was different.  Yes, the M68 breech oriented in the vertical plane, but it is also round.  But beyond shape, there is the the necessity of the gun tube itself to act as the piston of the recoil system.  Whereas the L7 utilized external recoil cylinders and return springs, the M68 uses a concentric recoil cylinder.  So you see even if the breech threads are the same pitch and number, and even if the retaining pin and plug are the same (they may well be), there is no way an L7 Tube will work in an M68s mount because it isn't machined to act as a piston.

 

 

The basic external profile of both barrels are the same. AFAIK with the concentric recoil system the ordnance is fitted into a sleeve  which forms the inner element of the hydraulic recoil system and provides the mount for the counter recoil spring.

[bojan]

 

Just for completeness, there was one additional British ordnance developed that can be included in the lists..     

The 3.7" AA ordnance was used towards the end of the war as the basis for the 32 pounder (94mm) ordnance of the experimental Tortoise anti-tank vehicle. (https://en.wikipedia...e_QF_32-pounder).

 

I was only noting guns that ended in the production tanks.