Question: Weapons sizes

[chris h]

Does anyone know why some weapons have odd sizes although perhaps odd is not correct word?

For instance the German 88mm. Why not 90mm or 85mm? Another example would be the 81mm mtr or the 7.92mm mg.

[scorpio_rocks]

Quick answer - No reason at all!

The gunsmith designed the gun with what ever caliber he desired!

Some are the result of "conversions" from inches to mm (ie 12.5 or 12.7mm = .50 inch)

Also it depends often on what is being measured - sometimes it is bullet diameter, case diameter, bore diameter (with or without including rifleing), etc.

Often if a particular caliber round is available in large quantities you will design your weapon to match, perpetuating the number.

Often different manufaturers will measure/describe different things to mean the same size - look at the .38 special, it fires same size ammo as a .357.

[Suhiir]

Ammunition is a trade off between diameter/mass, powder charge/velocity, and if it has a warhead bursting charge.

Take the classic American .45 caliber M1911, big low velocity bullet and limited magazine capacity because of this. This is why many armies use 9mm handguns. Smaller higher velocity bullet and a much larger magazine capacity. Which is "better"? That's an argument that will never be resolved because it's more subjective then objective.

"Odd" calibers are because of this. You trade off caliber for mass, ammo capacity, and often velocity. Sure they make big high velocity ammo, but due to it's size it's HEAVY. This is why naval guns are generally larger then land based systems. You have a whole ship to store ammo and ammo handling equipment in.

[RetLT]

And what is with the British and their 6lb, 17lb, and 25lb guns?

How does the weight of the shell correspond to the diameter of the barrel and why on earth would anyone use such a system?

[scorpio_rocks]

Originally Posted by RetLT

And what is with the British and their 6lb, 17lb, and 25lb guns?

How does the weight of the shell correspond to the diameter of the barrel and why on earth would anyone use such a system?

It goes back to a time of cannonballs where a gun was rated and sized by what weight of shot it fired. (A similar reason spawned the "gauge" system for shotguns - ie 12 gauge fires a single ball 1/12 of a pound). With standardised composition of cannon shot it worked - everyone knew what was being measured, rather than "which diameter exactly?".

The system stayed even when cannon balls were no longer used giving us the WWII era 2 pounder (40mm), 3 pounder (47mm), 6pounder (57mm), 17pounder (76.2mm) and 25pounder (87.6mm) amongst others.

[troopie]

Originally Posted by Suhiir

Ammunition is a trade off between diameter/mass, powder charge/velocity, and if it has a warhead bursting charge.

Take the classic American .45 caliber M1911, big low velocity bullet and limited magazine capacity because of this. This is why many armies use 9mm handguns. Smaller higher velocity bullet and a much larger magazine capacity. Which is "better"? That's an argument that will never be resolved because it's more subjective then objective.

"Odd" calibers are because of this. You trade off caliber for mass, ammo capacity, and often velocity. Sure they make big high velocity ammo, but due to it's size it's HEAVY. This is why naval guns are generally larger then land based systems. You have a whole ship to store ammo and ammo handling equipment in.

I've always heard that the M1911 was designed to be a stopper. The pistols used by the US Army would not stop a Moro crazed on dagga and the M1911 was designed to do that. When it came into service the Moro uprising was long over, but that's an army for you.

troopie

[Suhiir]

Originally Posted by troopie

I've always heard that the M1911 was designed to be a stopper. The pistols used by the US Army would not stop a Moro crazed on dagga and the M1911 was designed to do that. When it came into service the Moro uprising was long over, but that's an army for you.

troopie

Personally I've always MUCH preferred the .45

[DRG]

Originally Posted by Suhiir

Personally I've always MUCH preferred the .45

I agree, mines aproaching it's 100th bithday......

[RetLT]

Originally Posted by Suhiir

Personally I've always MUCH preferred the .45

I was not a big fan of the .45. Too much kick, too heavy and limited ammo. The .40 Glock had less recoil and weight plus a larger ammo capacity.

[Suhiir]

Originally Posted by RetLT

I was not a big fan of the .45. Too much kick, too heavy and limited ammo. The .40 Glock had less recoil and weight plus a larger ammo capacity.

Never fired a .40, but I want to hit something once not need to use 3+ rounds making the larger ammo capacity pointless. This of course assumes you hit, true a larger ammo capacity give you more chances to do so.