"pounder" v. millimeter equivalents

[Noah_Vaile]

What, roughly, do a 2-pounder, six pounder and twenty-five pounder equal in terms of millimeters? Those Brits are so confusing and I presume the "pounder" doesn't refer to the cost of the weapon.

[PatG]

2 lbr = 40mm
3 lbr = 47mm (Tank gun only)
6 lbr = 57mm
13 lbr = 76mm (pre WWI piece some used as AA early WWII)
17 lbr = 76.2mm
18 lbr = 84mm (Field gun - some converted to 25lbr)
20 lbr = 84 0r 83.4mm (post WWII)
25 lbr = 87.5mm

There were others used in WWI but well out of service by WWII.

Keep in mind that other factors such as barrel length, type of round and charge used need to be considered when assessing the relative power of guns. While of equal calibre, the 25 lbr was much shorter than the German 88 and performance was much less as well. Similarily, the 17 lbr was much longer (and I believe had a heavier charge) than its Russian brothers so had considerably better performance.

Note that while often looked down on, for its time the 2 lbr was a kick *** AT gun.

[Andy_ONeill]

BTW. There is an official abbreviation of pdr rather than lbr. 6pdr (eg).

I think the 3pdr was much more likely to be found on ships than tanks by ww2.

British ATG used a much hotter load then US and more again than Soviet. Shells could be expected to be of higher quality than soviets, significantly so. Hence solid shells were less likely to shatter on impact and HE shells had more HE content for their calibre and probably more effective content as well. Soviet shells had to have thicker casings than most other countrues like german or US because they couldn't guarantee the tolerances. Iirc 15% less generally.
As if that wasn't enough, the fuses were less reliable.

[PatG]

Andy_ONeill said:
BTW. There is an official abbreviation of pdr rather than lbr. 6pdr (eg). ...

Sorry - I voluntarily took latin in highschool.

You're right about the 3pdr, I looked at weapons in the general time frame of the game - 30's to late 40's.

[Andy_ONeill]

It's quite odd really.
Though maybe less interesting to people less ww2 obsessed.
Anyhow and fwiw.

The British used a number of french 25mm ATG in 1940, which weren't too brilliant for that time even. They don't seem to have used any of the french 47mm though. Which they might have called 3pdr.
The French 47mm was a very good gun for that time but presumably the French didn't feel they had a surplus.

The 2pdr was good but the ammo wasn't so brilliant until late 1941 I think. The introduction of face hardening on pz4 particularly highlit the fact that the original design of AP had a tendency to shatter.

[Marek_Tucan]

How did the British call the 47mm Böhler gun? IIRC some were used with the paras before 6pdr.