[morzh]

Yes it will break the backelite.

Use the rivet you'd normally use. Like a proper length and diameter copper rivet.
Take the mandrel out of the barrel.
Insert the barrel like you would otherwise in the plug, and using a large tool with conical end, like a large screw exteactor, and a hamner, flare the protruding end which otherwise would be flared with the mandrel. Tap lightly, until fully flared. Works beautifully.