Those of us who have used CAV-15 lowers and had great results, were excited to see the concept reborn as the KP-15 from KE Arms. As great as the CAV-15 was, it was not without potential weak points including a small number of lowers that split at the weld between the two halves.
This CAV-15 issue is overblown to some extent but not without founding. It has also been projected onto the KP-15 for understandable reasons given the similarity of the concepts. However, it should be pointed it out that the KP-15 is not simply a rework of the original CAV-15 molds. It is an entirely new, ground-up effort – new engineering, new design, and new processes.
KE Arms recently shared a production process photo of a KP-15 lower that shows an example of how the KP-15 was designed with the process of linear vibration welding from the start with input from engineers that specialize in that process. The image shows an alignment tab that ensures that the process works as intended and can then be removed via machining after the process is complete. The result is a weld between the halves of the lower that has shown itself to be stronger than the surrounding material in testing.