Heck, I don't know how the firing pin rod main spring in the bolt would allow for a "slow" release to cause a misfire or hang fire. Hang fires are often due to bad or old primer chemicals that take time to explode once the primer is struck.  I have had many with old milsurp ammo.

When the sear is released, if the safety is off, the bolt should allow the striker on the firing pin rod via the main spring to strike the primer quickly with the force required to fire the primer. That is if the main spring is strong enough and clear to function properly.

In all of the dozens of Krag bolts I have dis-assembled and operated, I have yet to find a weak main spring. Says a lot for the spring metallurgy from Springfield Armory 120 years ago!