3" mortar -- Grogs ahoy!

[JasonC]

I don't believe a word of it, on .2 inches just by boring out the barrel. That would mean the barrel of the rifled 4.2 was 5mm thinner than the barrel of the old smoothbore.

Considering how thin mortar barrels are to start with that seems quite unlikely. With the increased charge used and windage going to zero to exploit rifling, you'd need it anything a thicker barrel not a thinner one.

A more likely explanation is that the site author is trying to explain the nomenclature difference and mentally connects it to the innovation of rifling in the US mortar.

There is precious little reason to take the initial Stoke's designations are hyper accurate statements of weapon caliber. They were meant simply to distinguish one mortar from another, the 3 from the 4 or the 2 (a heavier weapon, since it was a spigot design) or the 7.

Mortars of the Stokes design (used in everything we call a mortar, since) were new weapons (with little in common with older cannons so designated). Now, why would the French, copying the Stokes for their own use, decide to add 0.2 inches to the caliber? They didn't know an inch from their anatomy. Their own weapons were all half cm calibers - 60, 75, 105, 155.

If they had made an 80mm mortar it might plausibly be a new caliber. They didn't. It wasn't a new caliber, it was a legacy caliber. There is only one predecessor to it, the Stokes 3 inch. When one adds the report that someone measured a 3 inch in his possession and found it 81mm, one would have to argue he has a mid-IDed mortar, and the Brandt company used 81mm (and a hair) on a lark.

[Guest Mike]

Jason if yuo can provide some proof then I'd be happy to accept your claim, but you are arguing by reasoning without startign with a basis in fact.

For example Brandt may have originally designed his mortars to a requirement for a 75mm weapon, and his 60mm mortars are not 82mm, so why did he chose that calibre?

Why did the Russians make a 120mm mortar copy of the 81mm? etc

The reference given above for a 76.2mm calibre for teh 3" mortar is from a reputable document from a reputable publisher - I prefer that over your supposition any day.

But I'd be happy to see and accept evidence of a similar calibre (ha ha) supporting your case if you can find any.

[Guest Mike]

Jason if yuo can provide some proof then I'd be happy to accept your claim, but you are arguing by reasoning without startign with a basis in fact.

For example Brandt may have originally designed his mortars to a requirement for a 75mm weapon, and his 60mm mortars are not 82mm, so why did he chose that calibre?

Why did the Russians make a 120mm mortar copy of the 81mm? etc

The reference given above for a 76.2mm calibre for teh 3" mortar is from a reputable document from a reputable publisher - I prefer that over your supposition any day.

But I'd be happy to see and accept evidence of a similar calibre (ha ha) supporting your case if you can find any.

[dieseltaylor]

I do not share the high opinion of publishers ...... I suspect some prat has been told to update the books and has got rid of imperial measurements.

As far as I am concerned it was called a 3" mortar at the time it was used and thats what it should remain as ..... I confidently expect the fleets at Trafalger to be armed with 20kg cannon as their heavy guns.

Now I will accept that the text can translate for those non-imperial but when talking history it would be nice to keep the context.

That reminds me I must suggest metriction for Shakespeare's plays [ come to that English would be handy]

[dieseltaylor]

I do not share the high opinion of publishers ...... I suspect some prat has been told to update the books and has got rid of imperial measurements.

As far as I am concerned it was called a 3" mortar at the time it was used and thats what it should remain as ..... I confidently expect the fleets at Trafalger to be armed with 20kg cannon as their heavy guns.

Now I will accept that the text can translate for those non-imperial but when talking history it would be nice to keep the context.

That reminds me I must suggest metriction for Shakespeare's plays [ come to that English would be handy]

[Guest Mike]

The books were published in the early 70's IIRC - and have never been updated, nor were they reprints or updates of an earlier edition.

And they wouldn't be 20 kilo cannon - they'd be 8.2 kilo, 10.9 kilo, 16.4 kilo, 19.1 kilo and 30.1 kilo!!

Except of course the French also used pounds at the time for their cannon (Livre), except their pound was different from the English one, as were the Dutch, Russian, Neopolitan, Spanish and Danish pounds.......... and some cannon were "sized" by the weight of a stone shot that fitted the bore, not an iron one..... :eek:

[Guest Mike]

The books were published in the early 70's IIRC - and have never been updated, nor were they reprints or updates of an earlier edition.

And they wouldn't be 20 kilo cannon - they'd be 8.2 kilo, 10.9 kilo, 16.4 kilo, 19.1 kilo and 30.1 kilo!!

Except of course the French also used pounds at the time for their cannon (Livre), except their pound was different from the English one, as were the Dutch, Russian, Neopolitan, Spanish and Danish pounds.......... and some cannon were "sized" by the weight of a stone shot that fitted the bore, not an iron one..... :eek:

[Michael Dorosh]

The 3 inch mortar was a 76mm weapon; not sure what all the fuss is about. The 3 inch mortar was indeed replaced with the NATO standard 81mm well after WW II. Canada, like Britain, used and still used the 81mm mortar.

The 3-inch mortar was not an 81mm weapon.

Emrys is correct AFAICT also about the Russians using 82mm weapons, or at least we have read the same mythology texts.

[Michael Dorosh]

The 3 inch mortar was a 76mm weapon; not sure what all the fuss is about. The 3 inch mortar was indeed replaced with the NATO standard 81mm well after WW II. Canada, like Britain, used and still used the 81mm mortar.

The 3-inch mortar was not an 81mm weapon.

Emrys is correct AFAICT also about the Russians using 82mm weapons, or at least we have read the same mythology texts.

[JasonC]

Brandt made 60mm mortars because it was a French company so they used metric measurements as a matter of course. The same for the Russian 120mm. All the more reason to infer a legacy caliber from their use of 81mm (or 82mm, which is probably a different way of saying the same 81.3mm measurement).

There is no evidence Brandt was making a 75mm weapon. You don't miss by 6mm, it is an absurd idea. They were copying the Stokes 3 inch. They either deliberately added .2 inches in caliber for reasons of their own, without rounding to a metric measure 80mm, or the item they were copying from was already 81.3mm not 76.2mm. We know everyone else making 81mm later was copying Brandt or its licensees abroad.

Stokes designed his mortars in a few months after the outbreak of WW I. He was not a military man, just an inspired inventor who saw the need for a portable artillery piece. 3 inch field guns were a standard item in many armies, and he wanted to duplicate the hitting power of one in a more portable form.

He was not given some elaborately specified government contract that stipulated "the weapon shall have a bore of exactly 3 inches" - nothing remotely like that happened. Stokes' original model used a sheet metal tube, a fuse from a hand grenade, and a blank 12 gauge shotgun shell as the firing charge. It was a completely ad hoc weapon.

The British 2 inch mortar (by Vickers, aka the "Toffee Apple"), a spigot weapon firing a much heavier (60 lb) bomb than the 3 inch, had an actual internal caliber of 1.75 inches. But was called a 2 inch.

A "n inch" designation for a WW I mortar told you which weapon was being discussed. It simply was not meant to tell you the exact dimensions of the weapon.

[JasonC]

Brandt made 60mm mortars because it was a French company so they used metric measurements as a matter of course. The same for the Russian 120mm. All the more reason to infer a legacy caliber from their use of 81mm (or 82mm, which is probably a different way of saying the same 81.3mm measurement).

There is no evidence Brandt was making a 75mm weapon. You don't miss by 6mm, it is an absurd idea. They were copying the Stokes 3 inch. They either deliberately added .2 inches in caliber for reasons of their own, without rounding to a metric measure 80mm, or the item they were copying from was already 81.3mm not 76.2mm. We know everyone else making 81mm later was copying Brandt or its licensees abroad.

Stokes designed his mortars in a few months after the outbreak of WW I. He was not a military man, just an inspired inventor who saw the need for a portable artillery piece. 3 inch field guns were a standard item in many armies, and he wanted to duplicate the hitting power of one in a more portable form.

He was not given some elaborately specified government contract that stipulated "the weapon shall have a bore of exactly 3 inches" - nothing remotely like that happened. Stokes' original model used a sheet metal tube, a fuse from a hand grenade, and a blank 12 gauge shotgun shell as the firing charge. It was a completely ad hoc weapon.

The British 2 inch mortar (by Vickers, aka the "Toffee Apple"), a spigot weapon firing a much heavier (60 lb) bomb than the 3 inch, had an actual internal caliber of 1.75 inches. But was called a 2 inch.

A "n inch" designation for a WW I mortar told you which weapon was being discussed. It simply was not meant to tell you the exact dimensions of the weapon.

[JasonC]

Michael, you have now said twice that the 3 inch really was 3 inch aka 76mm. But what evidence do you have for this, besides your having thought so? I've thought so, but I consider my having thought so to be naive literalism without any thought behind it. It might still be right, but at least in my case it was not based on any direct evidence, sufficient to distinguish one from the other as referring to different physical dimensions rather than different nomenclature. If it nevertheless is right, the mystery is - where did 81mm come from?

[JasonC]

Michael, you have now said twice that the 3 inch really was 3 inch aka 76mm. But what evidence do you have for this, besides your having thought so? I've thought so, but I consider my having thought so to be naive literalism without any thought behind it. It might still be right, but at least in my case it was not based on any direct evidence, sufficient to distinguish one from the other as referring to different physical dimensions rather than different nomenclature. If it nevertheless is right, the mystery is - where did 81mm come from?

[Guest Mike]

Jason have a look at the 2nd post in this thread for the evidence - it is not just my "thought" - the book is explicit.

[Guest Mike]

Jason have a look at the 2nd post in this thread for the evidence - it is not just my "thought" - the book is explicit.

[Michael Dorosh]

Originally posted by JasonC:

[QB] Michael, you have now said twice that the 3 inch really was 3 inch aka 76mm.

I could have sworn I've only posted once in this thread before now. Of course, there are three Michaels/Mikes here now.

I have handled a 3-inch mortar (there is one in our regimental museum and I helped with the display) and I have fired the 81mm mortar (both the German Granatwerfer 34 and the Canadian postwar 81mm mortar.) The latter two were owned by a friend. They (the two 81s) are quite different from the 3 inch mortar. Both of the latter two mortars were used to fire 81mm illumination rounds, sans warhead (only way to do it legally).

3-inch mortar, Calgary Highlanders museum

Google turns up this, also:

http://www.mortarsinminiature.com/index_British%203.htm

A popular and effective weapon, the British 3 inch (76.2mm) Mortar served with distinction throughout it's relatively long career. Having first entered Commonwealth service in the early 1930s, the 3 inch Mortar served throughout WWII in all theaters of operations. It also served later on in the Korean War and could still be found in some Home Guard units up until the late 1970s. Eventually, the 3 inch Mortar would be retired in favor of the more common and standardized 81mm weapons. The major drawbacks of the 3 inch Mortar, other than the odd size caliber, was the weapon's weight and long flight times for the ammunition to reach the target.

Emphasis mine.

[ December 15, 2003, 09:16 PM: Message edited by: Michael Dorosh ]

[Michael Dorosh]

Originally posted by JasonC:

[QB] Michael, you have now said twice that the 3 inch really was 3 inch aka 76mm.

I could have sworn I've only posted once in this thread before now. Of course, there are three Michaels/Mikes here now.

I have handled a 3-inch mortar (there is one in our regimental museum and I helped with the display) and I have fired the 81mm mortar (both the German Granatwerfer 34 and the Canadian postwar 81mm mortar.) The latter two were owned by a friend. They (the two 81s) are quite different from the 3 inch mortar. Both of the latter two mortars were used to fire 81mm illumination rounds, sans warhead (only way to do it legally).

3-inch mortar, Calgary Highlanders museum

Google turns up this, also:

http://www.mortarsinminiature.com/index_British%203.htm

A popular and effective weapon, the British 3 inch (76.2mm) Mortar served with distinction throughout it's relatively long career. Having first entered Commonwealth service in the early 1930s, the 3 inch Mortar served throughout WWII in all theaters of operations. It also served later on in the Korean War and could still be found in some Home Guard units up until the late 1970s. Eventually, the 3 inch Mortar would be retired in favor of the more common and standardized 81mm weapons. The major drawbacks of the 3 inch Mortar, other than the odd size caliber, was the weapon's weight and long flight times for the ammunition to reach the target.

Emphasis mine.

[ December 15, 2003, 09:16 PM: Message edited by: Michael Dorosh ]

[Guest Mike]

Someone's just told me that Stokes patented his design, so Brandt could not have copied the calibre legally at all anyway.

I don't know whether this is true or not tho.

This source reckons 81mm was chosen because it provides more optimal bang for buck - 3" isn't a very good calibre (indeed the WW1 mortar was a shocker for range and effect) but the Brits were strapped for cash and unable to develop an entirely new weapon between wars, so they stuck with the tube and developed better projectiles. In WW2 the Brit mortar was still under-ranged compared to it's 81-82mm rivals.

However there is a 3" mortar on display a couple of hundred miles north of here, and if this is still going on after Christmas it'll be a good excuse to go visit the army museum again!!

[ December 15, 2003, 10:08 PM: Message edited by: Mike ]

[Guest Mike]

Someone's just told me that Stokes patented his design, so Brandt could not have copied the calibre legally at all anyway.

I don't know whether this is true or not tho.

This source reckons 81mm was chosen because it provides more optimal bang for buck - 3" isn't a very good calibre (indeed the WW1 mortar was a shocker for range and effect) but the Brits were strapped for cash and unable to develop an entirely new weapon between wars, so they stuck with the tube and developed better projectiles. In WW2 the Brit mortar was still under-ranged compared to it's 81-82mm rivals.

However there is a 3" mortar on display a couple of hundred miles north of here, and if this is still going on after Christmas it'll be a good excuse to go visit the army museum again!!

[ December 15, 2003, 10:08 PM: Message edited by: Mike ]

[JasonC]

"I have handled a 3-inch mortar"

Great. Have you measured its bore diameter?

"They (the two 81s) are quite different from the 3 inch mortar."

Wonderful. But are they .2 inches larger in bore diameter?

I am aware the nomenclature changed. I do not doubt that 99 out of 100 people hearing the two nomenclatures will assume, as I long have, that they are two different physical dimensions. But there is no reason to suppose it must be so.

If you have access to a 3 inch mortar in this museum display, you can settle the matter definitively by physically measuring its bore. No amount of citation can settle it, because it is just as likely the citee went by the name as well and assumed. One measurement can, because there is no room for such mistakes.

If it is 76mm, then we will have an interesting subsidiary mystery to explore, where the 81mm caliber originated.

[JasonC]

"I have handled a 3-inch mortar"

Great. Have you measured its bore diameter?

"They (the two 81s) are quite different from the 3 inch mortar."

Wonderful. But are they .2 inches larger in bore diameter?

I am aware the nomenclature changed. I do not doubt that 99 out of 100 people hearing the two nomenclatures will assume, as I long have, that they are two different physical dimensions. But there is no reason to suppose it must be so.

If you have access to a 3 inch mortar in this museum display, you can settle the matter definitively by physically measuring its bore. No amount of citation can settle it, because it is just as likely the citee went by the name as well and assumed. One measurement can, because there is no room for such mistakes.

If it is 76mm, then we will have an interesting subsidiary mystery to explore, where the 81mm caliber originated.

[Guest Mike]

If you're in America you might be able to get copies of hte inter-war US manuals for teh 3" Stokes mortar fairly easily from http://www.military-info.com/mphoto/P060j.htm

Jason your reaction against citation is perverse!! :eek:

[Guest Mike]

If you're in America you might be able to get copies of hte inter-war US manuals for teh 3" Stokes mortar fairly easily from http://www.military-info.com/mphoto/P060j.htm

Jason your reaction against citation is perverse!! :eek:

[Wisbech_lad]

Found this

"In WW I France bought 3000 Stokes mortars from the British. The French weren’t satisfied with the ammunition, but Edgar Brandt started to improve the weapon. In 1921 France issued a program for a 75 mm trench mortar. Eventually Brandt’s design of a new 81 mm mortar was approved. His design would be the base for almost every type of mortar in the world"

My guess would be that Brandt started with a 3" Stokes template, and added 5mm to make it 81mm, rather than 4mm to make it 80mm... Engineers have odd logic sometimes!

And on the 4.2", this site claims that it was because the US researchers bored out old 4" mortars to add rifling while experimenting to increase the range

http://www.4point2.org/mortar42.htm

This site seems fairly clear that the 3" (76mm)was replaced by the 3.2" (81mm) mortar in the British army

http://riv.co.nz/rnza/hist/mortar/mort15.htm

[Wisbech_lad]

Found this

"In WW I France bought 3000 Stokes mortars from the British. The French weren’t satisfied with the ammunition, but Edgar Brandt started to improve the weapon. In 1921 France issued a program for a 75 mm trench mortar. Eventually Brandt’s design of a new 81 mm mortar was approved. His design would be the base for almost every type of mortar in the world"

My guess would be that Brandt started with a 3" Stokes template, and added 5mm to make it 81mm, rather than 4mm to make it 80mm... Engineers have odd logic sometimes!

And on the 4.2", this site claims that it was because the US researchers bored out old 4" mortars to add rifling while experimenting to increase the range

http://www.4point2.org/mortar42.htm

This site seems fairly clear that the 3" (76mm)was replaced by the 3.2" (81mm) mortar in the British army

http://riv.co.nz/rnza/hist/mortar/mort15.htm