Along with the fibur barrel, this is just another fine example of DW's industry leading standard. I have tested many different bolts over the years and there are a few excellent designs out there, but when it comes to the best, you need not look any farther than here. I have shot case upon case through my ions with these bolts and have yet to have break or leak issues with maximum consistency and performance throughout. The center stalk is by far the best design that makes the most since of any design. Best bolt for the ION in the industry bar none!