I hate the copper (stuff is too kind) on general principles.

While not necessarily relevant to the Savage, we put it on shaft to hold sprockets on. Usually with a squeeze hub that the sprocket bolted to ( the hub and sprocket had tapered surfaces, so the bolting squeezed the hub to the shaft)

The stuff welded the hub onto the sprocket. If used with just a set screw bearing or sprocket, it welded them to the shaft.

Never used it for anything again, threw away what we had.