Re: Wear out an action?
There is an engineering design principal called "design for infinite life".
Steel, its alloys, and Titanium have a characteristic - the LACK of an "endurance limit". This means that properly designed, and loaded while in use, the part/assembly will last forever. Note that ONLY steel, its alloys, and Titanium lack an endurance limit. All other metals HAVE one, meaning that regardless of how heavy duty and robust the design is, it WILL fail.
That all said, I would hope that actions are designed for infinite life, but honestly, I doubt it. I doubt this because most actions were designed and developed long before the infinite life principles were well understood. Additionally, when I (by eye) analyze most actions, they look light duty to me. Lastly, 100k cycles is LOW in the scheme of design for infinite life. Couple that with the fact that FEW guns see that kind of use, and my gut tells me actions will wear out and fatigue eventually, but none of us will probably ever do it.