Right, if you've read a lot of his other write-ups and books, you'd know his emphasis is on long range hunting and that means lower impact velocity shots. This article was written to educate the long range hunter on the factors and possibilities of using certain copper bullets at certain impact velocities and certain impact resistance.Interesting article and a bit contradictory of his cartridge research. Not sure why Foster published this. In every cartridge article I have read of his, he has nothing to say but praise for Barnes bullets. The only negative is if the velocity has dropped to below the velocities that even Barnes has indicated, then expansion is reduced, or non-existant.
Never read his reviews of any monolithics other than Barnes.
Cup and core bullets not designed for low velocity expansion can fail at long range as well.
He's said plenty about how copper bullets do indeed have their place and are good choices when you take everything into account and need what they provide versus certain cup and core bullets.
He's also said plenty about how there are several poor choices in cup and core bullets too. People read and conclude what they want to though, to include not reading everything and seeing the whole big picture.