.................. The perforated tube anyone uses rattles around and falls apart. There needs to be a solid part at each end for the core for it to not destroy itself. .............
The solid band at each end will help but may still fracture if you make the cores out of 20 or 24 gage material.
I make my cores out of 16 and 18 gage material. Using this material makes the silencers heavy, and are time consuming to build, but the cores are bullet proof.