[Mike Irwin]

"I once read that the reason for that is that there never was much .455 (or .380 Revolver) made. You got 12 or 18 rounds when you were issued your revolver and that was it, there was not a large resupply plan. After all, who shoots at people with a revolver except in dire emergency? Maybe some sneaky commando types and a lot of them went over to FNs. "

The British never put much emphasis on production of handgun ammo post WW I, that is true.

When the Enfield .38 was adopted in the 1920s the original 200-gr. LRN bullet served until sometime in the 1930s when it was realized that its use might be against the Hague Convention, so the jacketed 180-gr. RN, the Mk II, cartridge was adopted.

When war broke out in 1939 and Britain began to mobilize it was quickly discovered that there wasn't nearly enough of the new Mk II ammo to supply the army, and many troops issued handguns went to France with the old 200-gr. LRN cartridges.

When Britain came to the United States for handguns they also came for ammo. They were (especially after Dunkirk) so desperate for ammo that they took anything US companies could produce, which led to the British getting a lot of .38 S&W ammo loaded with the more American standard 145 to 158-gr. bullets as well as "Super Police" ammo, which was loaded with 200-gr. lead bullets.

Most of that ammo was apparently used for training (although I have heard reports that some commercial American lead loads were issued to troops in Africa) while standard service ammo was loaded in Britain and contracted from Canada.