Rivet holes tearing ar a common problem with jardines. I bought one that was damaged and had to cut roughly 1.5in off the outer case. The big issue with mine was that the inner perfect tube was too short and when the packing burnt out it allowed the core to fall one end. Once the core fell it acted as a pulse hammer against the other end rippi g out the rivet holes.
If you take the time to do the job right take a few measurements you ahold never have the issue again. I also used 12 stainless rivets instead of the 6 Jardine uses.