Hello Chris and a big welcome to you.
Just to add for those interested Gunmetal and leaded bronzes are still widely used and in raw form like bar and pipe they show a characteristic banding pattern from the zinc and lead content that you dont get so much with other grades. You cut through this skin when machining so the banding disappears but you still get traces of grey clouding on the surface. its brilliant stuff, cuts beautifully and is well suited to certain bearings and gear combos, couldn’t be without it.

Here’s a visual comparison of a few very different bronzes in bar form, from left to right they are aluminium bronze, gunmetal as above, porous oilite and phosphor bronze. Unlike gunmetal, aluminium bronze can be a pig to machine and tap and I dread to think how much a stub of it this size would cost now!

BTW Gary I saw the dual Chubb on eBay but been that sidetracked with things i forgot to bid on it, have you picked it open yet?