In this post, Heavy 20 stands for a 20 gauge double barreled shotgun, made to shoot 12-gauge loads, and produced before or immediately after the first World War.
In Russia, their population was due to the writings of one Sergei Ivaschentsev. At the end of the XIX century he published a number of articles on the topic of the universal (all-around) gun. His logic was simple if the introduction of smokeless powders caused the turn to small bores with a noticeable increase in range and overall efficiency in rifles, the same principles ought to be applied to shotguns, and the perfect gun was a 20 bore strong enough to shoot 12-bore loads and weighing about 7 pounds (sort of like 20 ga. 3 magnum 60 years before).
He had the Royal Armory in Tula make heavy 20s of the Ivaschentsev system (I wonder how much Ivaschentsev there was in the system, because the guns looked a lot like the Rugby rising bite underlever sidelocks). This was before progressive-burning powders, so to make the 20-bore gun to shoot 32 gr./1 1/8 oz of shot safely, the barrel walls had to be so thick, that the guns ended up weighing over 7 1\2 pounds, and actually close to 8.
These guns had quite a bit of a following in Russia. A few people of note had heavy 20s, especially biologists who used them for collecting specimens of wildlife (so the attraction might have been that a heavy 20 shot better than a 12 with small loads, while allowing the use of 12-bore loads as well). Some Russians, obviously, ordered their heavy 20s abroad; one famous biologists had a Scholberg, another a Sauer. Ive seen pics of Belgium-made Greener of the type, and saw a 1927 classified offering to trade a Holland Royal Deluxe, 20 gauge weighing about 8 pounds, for a London best 12-bore game gun.
Ivaschentsevs System was dropped with the World War, but TOZ made quite a lot of their Model B hammer guns as heavy 20s between the Wars and after WWII (some of the reason behind these guns was the production costs, the outer dimensions of the barrels and the action being exactly the same as the regular 16-gauge guns). The one I handled, belonging to a farmer, weighed exactly the same as the farmers other gun, the MP153 semiauto. The farmer saw no reason to own the 20 that weighed like a 12, and wanted to sell it, I saw no reason in the 20 for 12 either, so I didnt buy it, but thats neither here nor there.
My question is, was this Heavy 20 thing, in the pre-WWI period, something that happened only to Russia, or was this trend to shift to smaller bores with the same load noticeable in Britain/America/Europe either? In other words, have you seen any heavy 20 guns or read a mention of them in period press?
