Larry, I think it's about 6 of 1, and a half dozen of the other, I've run both, and it's usually something else takes them out, before they wear out. I'm assuming the aluminum ones are made out of T7, which is pretty close in strength to steel, in this application, I've seen some pretty ragged looking one's of both materials. Yes, you can machine the steel one's down and get them light, but not as light as the T7, and by then, the strength is gone. I've actually turned the T7 one's down, quite a bit, to get clearance in the tube, and they've held up OK, like I said, something else usually gets them first. Bob
