Pure Copper Shot.

UPDATED 

In Italy, reloading website Siarm lists a product called "Real Copper". It is said to be made of 99.97840 % pure copper and is currently available in #3 and # 6 shot sizes for reloading. I also found a recipe on the same site for a 12 gauge test load composed of 28 grams of pure copper shot and 2 grams of B&P's MBx36 powder. Test results indicated that it produced a peak pressure of 750 bar and a velocity of 450m/s (about 1475 f/s). 

And here is a video of Dual Shock shells being tested in the fields of Argentina and the UK:



Naturally, with all the buzz around copper shot in Europe, I have to wonder if it will ever make its way over to this side of the ocean. But that brings up a whole slew of other questions. Here are a few I can think of, and my best guesses as to what the answers might be. 

Is copper shot approved for use in North America? 

I don't really know. But if I had to guess, I would say that copper shot should be perfectly fine to shoot wherever lead can be shot. But pellets made of pure copper are not on the list of approved non-tox lead alternatives. However, as an ingredient in shells combining different elements, copper gets the green light. Here are the percentages currently allowed in approved non-tox shot types.

Is pure copper shot toxic? There is no such thing as a completely non-toxic metal suitable for use in shotgun shells. So it comes down to figuring out which is the least toxic. And copper seems to have relatively low toxicity, especially when compared to lead. When copper is just one ingredient mixed with other things like tungsten, studies indicate that "the rate of copper release from tungsten bronze shot was 30 to 50 times lower than that from the copper shot, depending on pH".  And other studies indicate that the "mortality among mallards fed iron, copper, zinc-coated iron or molybdenum-coated iron shot was significantly less than in birds fed lead shot, and was not significantly greater than the controls."

I am sure there are many more studies out there, all of which undoubtedly reveal at least some level of toxicity, but what is important to note is that regulators in Europe, where environmental regulations tend to be far stricter than in the US or Canada, have determined that pure copper shot can be used where lead is banned. And that means they've chosen it (and other metals like bismuth and tungsten) as the 'least bad' alternatives to lead. 

Can it be shot out of a gun that is not approved for steel? I think so. But don't quote me on that. In terms of hardness, copper actually looks like it might fit the bill. It is harder than lead and bismuth, but it is softer than most of the others, including ITX (original) and Tungsten polymer, both of which were specifically designed for use in guns not approved for steel.

Copper is harder than lead, but softer than ITX and Tungsten Matrix shot

In terms of density, here is how it stacks up to some of the other options.

Copper shot is nearly15% denser than steel shot