amazing, I would think the 230 grains bullet would do a lot of damage on such birds. I would made a short insert barrel in the size of a loaded cartridge for the 25 ACP which would be the right thing with its fmj bullet.
have you ever try to load the .458 2" with the .410 2" shot load, must fit into the case.
but what happen on the traget after 20 meter?