^ Some back story, I already had the early gen1 that had the cube grafted onto the steel bolt. That ran around 750rpm even though bolt velocity wasn’t high (brass wasn‘t ejected far) the bolt hit the backplate which would make one handed shooting difficult as the gun would pitch upward.
A friend owned both the full tungsten and all A bolts made up to that point. The full tungsten was purposely set up slow probably around 600rpm but I found it so choppy I didn’t want to spend more than 2 magazines checking it out.
The A bolt was set up slow (don’t remember rpm) but of all the bolts it was Goldilocks. In the future I was offered to purchase that bolt and I knew I wanted it faster/smoother…. so just went about it methodically with a new spring. When we cut 4 coils and it ran 852rpm and was reliable I stopped there.
With that all said, in regards to your question if a new spring was used a while, would it have slowed down? Perhaps, but it couldn’t cycle the 2nd round so it would never become a used spring at that rate 😝. So the end result with 4 coils cut, if it ran slower after that being used I couldn’t tell, wouldn’t have been by much.
Sold that bolt and m11/9 and now have a .380a1 converted to 9mm with an A bolt so it’s a whole different animal. Right now set up fast as possible (strong spring to protect backplate welds) around 1250rpm. It’s 100% reliable and feels great to shoot. Leaving it alone.
