3" mortar -- Grogs ahoy!

[Mikko H.]

In the game it says that the 3" mortar has a caliber of 76.2mm. It seems only logical, but is it actually? I've read & heard that the 3" Mortar was actually an 81mm piece. Anyone out there can confirm/refute this?

[Mikko H.]

In the game it says that the 3" mortar has a caliber of 76.2mm. It seems only logical, but is it actually? I've read & heard that the 3" Mortar was actually an 81mm piece. Anyone out there can confirm/refute this?

[Stalin's Organ]

Yes it is actually 76.2mm (MacDonald's and Janes "Fact Files" series on Mortars and rockets)

[Stalin's Organ]

Yes it is actually 76.2mm (MacDonald's and Janes "Fact Files" series on Mortars and rockets)

[Mikko H.]

Some time ago we had a discussion on this subject on an e-mail list I subscribe to. One listmember brought the discussion to an end by actually measuring the tube of a 3" mortar he had access to, and confirmed it to be 81mm (or somesuch -- I think all the 8cm, 81mm and 82mm mortars are actually around 81.5mm).

[Mikko H.]

Some time ago we had a discussion on this subject on an e-mail list I subscribe to. One listmember brought the discussion to an end by actually measuring the tube of a 3" mortar he had access to, and confirmed it to be 81mm (or somesuch -- I think all the 8cm, 81mm and 82mm mortars are actually around 81.5mm).

[Wisbech_lad]

Another UK grog question.

I can understand the "pdr" nomenclature, actually like it and the link to naval history (2,6,17,20,25 pdr vs 40,57,76,84,88mm)

But why wasn't it consistent? Mortars are in diameter, so are some arty (4.5", 5.5", 7.2", 3" CS, 95mm CS)

When did the RN switch to calling guns by calibre, not weight? And why didn't the RA follow suit?

Of course, expecting consistency from the British armed forces is madness, but...

[Wisbech_lad]

Another UK grog question.

I can understand the "pdr" nomenclature, actually like it and the link to naval history (2,6,17,20,25 pdr vs 40,57,76,84,88mm)

But why wasn't it consistent? Mortars are in diameter, so are some arty (4.5", 5.5", 7.2", 3" CS, 95mm CS)

When did the RN switch to calling guns by calibre, not weight? And why didn't the RA follow suit?

Of course, expecting consistency from the British armed forces is madness, but...

[Amedeo]

The 'pounder nomenclature' was consistent when it was first used (XVIII cent.). Guns fired mainly spherical solid shot, hence, given the calibre of the gun you could have univocally determined the weight of the projectile. Howitzer and mortars fired mainly explosive shells, so they were identified by their calibre in inches.

This was common also with other armies of the period, but the British Army continued with this tradition... a little longer!

Thus the 3" mortar is perfectly consistent with the old classification , since only the guns were identified by the 'pounders'.

Regards,

Amedeo

[Amedeo]

The 'pounder nomenclature' was consistent when it was first used (XVIII cent.). Guns fired mainly spherical solid shot, hence, given the calibre of the gun you could have univocally determined the weight of the projectile. Howitzer and mortars fired mainly explosive shells, so they were identified by their calibre in inches.

This was common also with other armies of the period, but the British Army continued with this tradition... a little longer!

Thus the 3" mortar is perfectly consistent with the old classification , since only the guns were identified by the 'pounders'.

Regards,

Amedeo

[Michael Emrys]

Originally posted by Mikko H.:

Some time ago we had a discussion on this subject on an e-mail list I subscribe to. One listmember brought the discussion to an end by actually measuring the tube of a 3" mortar he had access to, and confirmed it to be 81mm (or somesuch -- I think all the 8cm, 81mm and 82mm mortars are actually around 81.5mm).

This was John D. Salt (where is John these days anyway?) and the figure he mentioned was 81mm. But I accept that what you say about the true figure coming out to 81.5mm as likely. On the other hand, I remember reading tales of the Germans being able to fire their 81mm ammo through captured Soviet 82mm tubes, but the converse not working. Can't say if that's an accurate representation of the facts.

Michael

[Michael Emrys]

Originally posted by Mikko H.:

Some time ago we had a discussion on this subject on an e-mail list I subscribe to. One listmember brought the discussion to an end by actually measuring the tube of a 3" mortar he had access to, and confirmed it to be 81mm (or somesuch -- I think all the 8cm, 81mm and 82mm mortars are actually around 81.5mm).

This was John D. Salt (where is John these days anyway?) and the figure he mentioned was 81mm. But I accept that what you say about the true figure coming out to 81.5mm as likely. On the other hand, I remember reading tales of the Germans being able to fire their 81mm ammo through captured Soviet 82mm tubes, but the converse not working. Can't say if that's an accurate representation of the facts.

Michael

[Andreas]

Originally posted by Amedeo:

The 'pounder nomenclature' was consistent when it was first used (XVIII cent.). Guns fired mainly spherical solid shot, hence, given the calibre of the gun you could have univocally determined the weight of the projectile. Howitzer and mortars fired mainly explosive shells, so they were identified by their calibre in inches.

This was common also with other armies of the period, but the British Army continued with this tradition... a little longer!

Thus the 3" mortar is perfectly consistent with the old classification , since only the guns were identified by the 'pounders'.

Regards,

Amedeo

What about the 4.5" howitzer?

[Andreas]

Originally posted by Amedeo:

The 'pounder nomenclature' was consistent when it was first used (XVIII cent.). Guns fired mainly spherical solid shot, hence, given the calibre of the gun you could have univocally determined the weight of the projectile. Howitzer and mortars fired mainly explosive shells, so they were identified by their calibre in inches.

This was common also with other armies of the period, but the British Army continued with this tradition... a little longer!

Thus the 3" mortar is perfectly consistent with the old classification , since only the guns were identified by the 'pounders'.

Regards,

Amedeo

What about the 4.5" howitzer?

[Amedeo]

Originally posted by Andreas:

What about the 4.5" howitzer?

If you look at my previous post you may read: howitzer and mortars...

Regards,

Amedeo

[Amedeo]

Originally posted by Andreas:

What about the 4.5" howitzer?

If you look at my previous post you may read: howitzer and mortars...

Regards,

Amedeo

[JasonC]

The original Stokes mortars were designated the 3 inch and the 4 inch. But the latter was apparently 4.2 inch caliber - it is the immediate ancestor of the US 4.2 inch "chemical" mortar. The chemical idea about its use was inherited from the Stokes 4 inch, which was used in the same capacity. (3 inches were thought to have too small a payload for decent gas delivery). It would not be surprising for the 3 inch to also be 3.2 inch in actual caliber - which is 81.28mm.

The Brandt mortar of 1927, 81mm by official designation and the predecessor of nearly everyone's later 81mm mortars, was a direct descendent of the WW I era Stokes 3 inch. There is no obvious reason a French company would have adopted 81mm as the caliber of the weapon if it weren't already in use. So it is likely the 3 inch designation was a loose expression, just like the 4 inch designation, while the actual bore size was 3.2 and 4.2 inches respectively.

[JasonC]

The original Stokes mortars were designated the 3 inch and the 4 inch. But the latter was apparently 4.2 inch caliber - it is the immediate ancestor of the US 4.2 inch "chemical" mortar. The chemical idea about its use was inherited from the Stokes 4 inch, which was used in the same capacity. (3 inches were thought to have too small a payload for decent gas delivery). It would not be surprising for the 3 inch to also be 3.2 inch in actual caliber - which is 81.28mm.

The Brandt mortar of 1927, 81mm by official designation and the predecessor of nearly everyone's later 81mm mortars, was a direct descendent of the WW I era Stokes 3 inch. There is no obvious reason a French company would have adopted 81mm as the caliber of the weapon if it weren't already in use. So it is likely the 3 inch designation was a loose expression, just like the 4 inch designation, while the actual bore size was 3.2 and 4.2 inches respectively.

[Guest Mike]

Post war the British adopted the 81mm mortar in the late 50's - are we getting confused between this and the 3"

I've never heard any suggestion that the 3" was anything other than 3" until now.

[Guest Mike]

Post war the British adopted the 81mm mortar in the late 50's - are we getting confused between this and the 3"

I've never heard any suggestion that the 3" was anything other than 3" until now.

[JasonC]

Did you ever hear that the Stokes 4 inch in British service in WW I was actually 4.2 inches? (Why would you?) Do you have any other explanation for where 81mm came from, as the chosen caliber of the Brandt mortar of 1927?

[JasonC]

Did you ever hear that the Stokes 4 inch in British service in WW I was actually 4.2 inches? (Why would you?) Do you have any other explanation for where 81mm came from, as the chosen caliber of the Brandt mortar of 1927?

[Guest Mike]

No I haven't heard that about the 4" - indeed this site (http://www.4point2.org/mortar42.htm) says that it is not true, and the first American 4.2" was made by boring out the 4" barrel by .2" - which might be difficult if it was 4.2" already!

Another explaination for the 81mm is not required - there really hasn't been any solid proof offered that 3"=81mm, and absence of evidence is not evidence of absence - I'm surprised to see you using such an argument!! :eek:

[Guest Mike]

No I haven't heard that about the 4" - indeed this site (http://www.4point2.org/mortar42.htm) says that it is not true, and the first American 4.2" was made by boring out the 4" barrel by .2" - which might be difficult if it was 4.2" already!

Another explaination for the 81mm is not required - there really hasn't been any solid proof offered that 3"=81mm, and absence of evidence is not evidence of absence - I'm surprised to see you using such an argument!! :eek:

[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.