Skip them.
If such things matter to you, they are copper coated steel cased. The jacket is tubular, with an open base like military FMJ's without the rollover on the base, and open tipped like match bullets.
Some folks on this board will have you believe you have to rebarrell after a half dozen of them go down your barrel .
They shoot worse than 55gr Winchester FMJ's, if you can beleive that. They should be more accurate than they are - stout open base with a recessed lead base, and open tip like a match bullet. I have about 800 of a 1000 bullet order left. I was going to use them for standing slowfire practice but I can shoot offhand better than they can shoot...