Quote Originally Posted by ssj View Post
alloy/aluminum was used during/late ww2? but this is a southern hemisphere repair. The weird thing I found on one gun was it had copper plates but steel screws
As sailors and boat restorers are quickly taught, never put aluminum and copper/brass near each other. They create galvanic reaction, just like a battery; an electrolytic reaction will occur, resulting in the destruction of the aluminum. It's accelerated wherever salt is present in the atmosphere. That's why all aluminum for marine applications are special alloys. Brass, copper, and steel are okay as partners.