[Avenger]

Little background here: I was watching something on the Outdoor channel the other day, a 3 gun shoot. Rifle, shotgun, and pistol over a course. It looked like a ton of fun. One of the competitors had gone vintage, running the course with an M1 Carbine, unknown pump shotgun, and a 1911, all of them WW2 vintage. He didn't do too bad.
That got me thinking about doing the same thing with other nations from WW2. Does anyone know if Britain, Germany, the USSR, and Japan ever standardized combat shotguns, or even employed them at all? I can see the Russians would have used anything that went bang, given some of the battles they were in, but I've never seen a word about shotguns in use by the militaries of the other participants.
BTW, I know about the Luftwaffe drilling guns, but were they actually carried aboard aircraft in combat?

[dfariswheel]

Foreign countries made very little official or even unofficial use of shotguns until quite recently.

The British made some use of shotguns unofficially in the trenches of WWI, and some use in the "Emergency" in Malaya in the 1950's, but that's about it.

Up until recent times, the combat shotgun was pretty much an American "thing".
Strangely, the current war is a "Shotgun war" with extensive use of shotguns in Iraq by both sides.

[Sunray]

Using a shotgun in war is contrary to the Rules of War. The Geneva or the Hague Convention, I forget which one. The U.S. is a relatively recent signatory of both. Both of these apply to declared wars against another country. The current martial festivities isn't a war. Despite the casualty figures. It's anti-terrorist action. You can't legally declare war on a terrorist group or an individual.
"...actually carried aboard aircraft..." Likely in bombers and transport aircraft only. There's no space in a fighter. Especially an Me-109.

[Jim K]

It is the Hague convention that prohibits use of soft point or expanding (including solid lead) bullets. The Geneva convention deals with prisoners of war.

The problem is that both deal with war between signatory nations, not with fighting internal crime or international terrorism. Al Qaeda is not a nation, and has not signed any conventions. Out of that simple fact come a lot of complications, like are Al Qaeda captives prisoners of war, or terrorist criminals? Do they deserve any protection or even recognition by U.S. courts, or any court? (Many German prisoners were held in the U.S., Britain, and Canada during WWII. I don't recall that they were allowed to appeal to the courts for their freedom.)

During the actual Iraq war, when the U.S. was fighting the Iraqi armed forces, Iraqi prisoners were undeniably POWs and were treated as such. But what status does a civilian setting off a roadside bomb have? Some folks, mainly Democratic party and civil rights leaders, say that anyone captured by U.S. forces anywhere, under any circumstances, should enjoy all the rights of a U.S. citizen. I not so respectfully disagree.

Jim

[Cosmoline]

Using a shotgun in war is contrary to the Rules of War.

No, it is not. Germany claimed this during WWI, but to no avail. We've been using combat shotguns continuously since.

[Avenger]

I figured the drillings were for larger aircraft. And I'll bet they weren't bothered with once actual combat began, as Lugers and p38s were much easier to carry.
I can see why Japan didn't use them, since most Japanese hadn't seen a firearm until they started training. No big game, no real tradition of hunting, and rigid societal rule all adds up to: no shotguns.
But Germans certainly spent a lot of time capering about with various scatterguns, as did the British.
The truth is, I just want something to fit in with my Mosin and Tokarev, and I can't afford a PPsh-41.

[SDC]

The drillings were carried as survival weapons, for emergency hunting, etc., and not for a "fighting" arm. As for the main part of your question, most armed forces steered clear of the shotgun simply for the fact that they're short-range firearms, and (unless you want to teach your troops ANOTHER manual of arms), they would've just used their issue rifles. Since many US troops already had at least a little familiarity with shotguns, that wouldn't have been such a big deal, but they still ended up being used only for MP and guard duty (though I think I do remember a very few instances of use during WW1, in the trenches).

[Sunray]

This is from the U.S. Army's manual on Military Law.
"34.
Employment of arms, etc., causing unnecessary in-jury.-It is especially forbidden * * * to employ arms, projectiles, or material calculated to cause unnecessary injury
(H.R., art. 23, par. (e))."
Only the U.S. JAG decided shotguns are OK for combat in response to a German complaint about the use of shotguns during W.W. I. Given that the U.S. was actively at war with Germany at the time, it's not surprising the JAG decided in favour of the use of shotguns. However, the JAG has no jurisdiction over anybody but U.S. forces.
The Hague Convention won't let you pillage either.