Actually there is something that happens when rifle cases stretch too far. The brass soon gets paper thin, and headspace separations occur. In fact, this happens quite often, and it can happen with almost ANY rifle cartridge - including your Dasher.
The first firing is especially tough on belted magnum calibers
because of the excessive shoulder clearance with factory loads, but these cases always survive the first
firing when the brass is still soft and maliable.
repeated loadings with excessive shoulder bump will stretch, harden, and thin the brass.
Case stretching leads to headspace separation.
This picture shows a belted case that had the shoulder bumped a bit too far back, and it was loaded three times. This case had no signs of wear on the outside, but as you can see the wear begins on the inside of the case. The next firnig would rip this case apart.
What I'm saying is this is "case stretching should be avoided as much as possible, and your cases will last a whole lot longer."