Convert pounders to mm for guns

Matrix Games Forums

Forums Register Login Photo Gallery Member List Search Calendars FAQ

My Profile Inbox Address Book My Subscription My Forums Log Out

Convert pounders to mm for guns

View related threads: (in this forum | in all forums)

Logged in as: Guest

Users viewing this topic: none

Printable Version

All Forums >> [New Releases from Matrix Games] >> War in the Pacific: Admiral's Edition >> Convert pounders to mm for guns

Page: [1]

Message

<< Older Topic Newer Topic >>

Convert pounders to mm for guns - 5/13/2017 1:39:38 PM

woods

Posts: 70
Joined: 10/29/2006
Status: offline

I always get confused above the above.

Read the following on the web :

I quote "There's no fixed forumla relating diameter to designation. The name - 20 pdr, 17 pdr, 6 pdr, etc, refers to the weight of the ammunition (just the shell I believe, not the complete cartridge). The weight will vary with both the diameter and legnth of the ammunition, so it's not as simple as you would hope.

That said, cannons tended to settle on standard sizes, and the pdrs were just the British versions of those. They were roughly equivalent to other nations' cannons of the same size. The common tank guns were

2 pdr: 40 mm

3 pdr: 47 mm

6 pdr: 57 mm

17 pdr: 76 mm

The 20 pdr was a post-war 84 mm tank cannon.

The 25 pdr was a field gun/howitzer, and was 88 mm

The 32 pdr was an anti-aircraft canon originally and was 96 mm".

The link :

http://forum.wotblitz.com/index.php?/topic/42312-conversion-of-british-gun-caliber-pounder-to-millimeters/

_____________________________

Art by Rougeusmc

Post #: 1

RE: Convert pounders to mm for guns - 5/13/2017 3:36:26 PM

BBfanboy

Posts: 18046
Joined: 8/4/2010
From: Winnipeg, MB
Status: offline

quote:

ORIGINAL: woods

I always get confused above the above.

Read the following on the web :

I quote "There's no fixed forumla relating diameter to designation. The name - 20 pdr, 17 pdr, 6 pdr, etc, refers to the weight of the ammunition (just the shell I believe, not the complete cartridge). The weight will vary with both the diameter and legnth of the ammunition, so it's not as simple as you would hope.

That said, cannons tended to settle on standard sizes, and the pdrs were just the British versions of those. They were roughly equivalent to other nations' cannons of the same size. The common tank guns were

2 pdr: 40 mm

3 pdr: 47 mm

6 pdr: 57 mm

17 pdr: 76 mm

The 20 pdr was a post-war 84 mm tank cannon.

The 25 pdr was a field gun/howitzer, and was 88 mm

The 32 pdr was an anti-aircraft canon originally and was 96 mm".

The link :

http://forum.wotblitz.com/index.php?/topic/42312-conversion-of-british-gun-caliber-pounder-to-millimeters/

I always thought the 17 pounder was about 90mm - based on the mounting of the gun on the Sherman chassis to create a "Firefly" tank. I know it could pierce a Tiger's frontal armour at normal battle ranges. I may be confusing the 90mm figure with later tanks that carried that bore.

_____________________________

No matter how bad a situation is, you can always make it worse. - Chris Hadfield : An Astronaut's Guide To Life On Earth

(in reply to woods)

Post #: 2

RE: Convert pounders to mm for guns - 5/13/2017 4:26:30 PM

Jorge_Stanbury

Posts: 4320
Joined: 2/29/2012
From: Toronto and Lima
Status: offline

Plus there is also the velocity of the projectile,

an early PzIV 7.5 cm KwK 37 L/24 short barrel, low velocity gun is not going to be the same as the long barrel/ high velocity 7.5 cm KwK 42 L/70 gun of a Panther

so you need to understand what kind of gun is that "xx" pounder you want to translate into mm

< Message edited by Jorge_Stanbury -- 5/13/2017 4:27:35 PM >

(in reply to BBfanboy)

Post #: 3

RE: Convert pounders to mm for guns - 5/13/2017 8:02:01 PM

woods

Posts: 70
Joined: 10/29/2006
Status: offline

Yes Jorge, I agree with you that the details are not that easy to convert. I was looking for the easy way out.

_____________________________

Art by Rougeusmc

(in reply to Jorge_Stanbury)

Post #: 4

RE: Convert pounders to mm for guns - 5/13/2017 10:15:23 PM

JeffroK

Posts: 6391
Joined: 1/26/2005
Status: offline

Its a British naming convention, probably goes back to Napoleonic era or earlier.
Like most things British it makes no sense

_____________________________

Interdum feror cupidine partium magnarum Europae vincendarum

(in reply to woods)

Post #: 5

RE: Convert pounders to mm for guns - 5/13/2017 10:25:13 PM

JeffroK

Posts: 6391
Joined: 1/26/2005
Status: offline

quote:

ORIGINAL: Jorge_Stanbury

Plus there is also the velocity of the projectile,

an early PzIV 7.5 cm KwK 37 L/24 short barrel, low velocity gun is not going to be the same as the long barrel/ high velocity 7.5 cm KwK 42 L/70 gun of a Panther

so you need to understand what kind of gun is that "xx" pounder you want to translate into mm

As only the British named their weapons in this way they are very consistant. As they didnt talk metric I imagine it was easier than using inches. (By the way, it interesting that while the United States is rooted in imperial measurement, its Army has used metric terms for almost 100 years)

The following link goes to the website of Tony Williams, one of the experts in ammunition
http://www.quarryhs.co.uk/ammotables.htm

_____________________________

Interdum feror cupidine partium magnarum Europae vincendarum

(in reply to Jorge_Stanbury)

Post #: 6

RE: Convert pounders to mm for guns - 5/13/2017 11:31:26 PM

woods

Posts: 70
Joined: 10/29/2006
Status: offline

Thanks JeffK for your link. Very informative.

_____________________________

Art by Rougeusmc

(in reply to JeffroK)

Post #: 7

RE: Convert pounders to mm for guns - 5/13/2017 11:41:09 PM

Reg

Posts: 2787
Joined: 5/26/2000
From: NSW, Australia
Status: offline

quote:

ORIGINAL: JeffK

Its a British naming convention, probably goes back to Napoleonic era or earlier.
Like most things British it makes no sense

Absolutely. It was the weight of a cannon ball...

_____________________________

Cheers,
Reg.

(One day I will learn to spell - or check before posting....)
Uh oh, Firefox has a spell checker!! What excuse can I use now!!!

(in reply to JeffroK)

Post #: 8

RE: Convert pounders to mm for guns - 5/14/2017 6:34:48 AM

Reg

Posts: 2787
Joined: 5/26/2000
From: NSW, Australia
Status: offline

quote:

ORIGINAL: JeffK

(By the way, it interesting that while the United States is rooted in imperial measurement, its Army has used metric terms for almost 100 years)

By coincidence I ran across this YouTube video today - The American Kilogram

Apparently the US signed the metre convention* and bases all customary units on SI standards.

* (also known as the Treaty of the Metre, is an international treaty that was signed in Paris on 20 May 1875).

P.S. The UK signed it too....

Who would have known.

< Message edited by Reg -- 5/14/2017 6:41:45 AM >

_____________________________

Cheers,
Reg.

(One day I will learn to spell - or check before posting....)
Uh oh, Firefox has a spell checker!! What excuse can I use now!!!

(in reply to JeffroK)

Post #: 9

RE: Convert pounders to mm for guns - 5/14/2017 7:32:13 AM

Chris21wen

Posts: 6249
Joined: 1/17/2002
From: Cottesmore, Rutland
Status: offline

quote:

ORIGINAL: JeffK

Its a British naming convention, probably goes back to Napoleonic era or earlier.
Like most things British it makes no sense

Try this
http://www.arc.id.au/Cannon.html

If it does not make sense to you good! That's how we like it confusion in the enemy ranks.

(in reply to JeffroK)

Post #: 10

RE: Convert pounders to mm for guns - 5/14/2017 7:34:24 AM

wdolson

Posts: 10398
Joined: 6/28/2006
From: Near Portland, OR
Status: offline

quote:

ORIGINAL: BBfanboy

I always thought the 17 pounder was about 90mm - based on the mounting of the gun on the Sherman chassis to create a "Firefly" tank. I know it could pierce a Tiger's frontal armour at normal battle ranges. I may be confusing the 90mm figure with later tanks that carried that bore.

The 17 pounder was roughly equivalent to the 75mm on the Panther. It was a long barrel high velocity 75/76mm gun. The Super Sherman built after the war had a US 90mm and it required a larger turret to accommodate the gun. The turret of the standard Sherman could take a low velocity 105mm howitzer, but it could only take a high velocity gun of around 75mm.

Bill

_____________________________

WitP AE - Test team lead, programmer

(in reply to BBfanboy)

Post #: 11

RE: Convert pounders to mm for guns - 5/14/2017 5:57:50 PM

BBfanboy

Posts: 18046
Joined: 8/4/2010
From: Winnipeg, MB
Status: offline

quote:

ORIGINAL: wdolson

quote:

ORIGINAL: BBfanboy

I always thought the 17 pounder was about 90mm - based on the mounting of the gun on the Sherman chassis to create a "Firefly" tank. I know it could pierce a Tiger's frontal armour at normal battle ranges. I may be confusing the 90mm figure with later tanks that carried that bore.

The 17 pounder was roughly equivalent to the 75mm on the Panther. It was a long barrel high velocity 75/76mm gun. The Super Sherman built after the war had a US 90mm and it required a larger turret to accommodate the gun. The turret of the standard Sherman could take a low velocity 105mm howitzer, but it could only take a high velocity gun of around 75mm.

Bill

Thanks Bill - that explains why I got 90mm stuck in my head for an up-gunned Sherman, while I also knew of the 17 pounder being used on the Firefly version.

_____________________________

No matter how bad a situation is, you can always make it worse. - Chris Hadfield : An Astronaut's Guide To Life On Earth

(in reply to wdolson)

Post #: 12

RE: Convert pounders to mm for guns - 5/15/2017 2:00:58 AM

Ian R

Posts: 3420
Joined: 8/1/2000
From: Cammeraygal Country
Status: offline

quote:

ORIGINAL: wdolson

quote:

ORIGINAL: BBfanboy

I always thought the 17 pounder was about 90mm - based on the mounting of the gun on the Sherman chassis to create a "Firefly" tank. I know it could pierce a Tiger's frontal armour at normal battle ranges. I may be confusing the 90mm figure with later tanks that carried that bore.

The 17 pounder was roughly equivalent to the 75mm on the Panther. It was a long barrel high velocity 75/76mm gun. The Super Sherman built after the war had a US 90mm and it required a larger turret to accommodate the gun. The turret of the standard Sherman could take a low velocity 105mm howitzer, but it could only take a high velocity gun of around 75mm.

Bill

When they put the 17 lber (76.2 mm, not exactly 3") in the Sherman they had to modify it & rotate it sideways 90 degrees, and the enlarged "high" rear turret bustle (an armoured box) acted as a counter-weight.

When designing the Comet tank, they produced a modified version of the 17 lbr and named it the 77mm . Like the US army 106mm and 107mm weapons, it was not actually that caliber. It also only ever equipped that tank. Can't remember if it fired the same ammunition as the Fireflies. I think the answer is 'no', hence the 77mm moniker, even though it was also a 76.2mm caliber weapon.

Eventually the first model Centurions could mount the 17 lbr right-way-up, but they soon moved on to the 20 lber OQF rifle, which was essentially an evolved 17 lbr. A decade or so later, when the T55 arrived, the 20 lbr was rebored, (it still fits the Centurion turret mountings), and turned into what became the NATO standard 105mm.

So, there you have it. The majority of the western world's tank fleets used the evolved 17 lbr gun for about 50 years