Remember that the spring's force = 0.5 * k * square(distance) plus mfg rated force.
So at zero distance, it is just 17 lbs or 23lbs, not much against the explosion. But as distance increases, force goes up by half of the distance squared. That goes up by the law of exponential squared. for practical purpose of early unlock, assumption of mfg rating and linear behavior is close enough.
Now, turn to the issue of "nearly" in battery, a strong spring would regenerate enough velocity and force from recoil, to slam it into full battery a little more authoritatively. Right?
Causes for short of full battery that I've seen are:
- Too long OAL.
- dirty gun, too much friction or impeding of slide action (case sliding into extractor not smooth)
- primer not fully seated.
I'm sure there's more, like improper dimension barrels. But in my experience, all of my current 10mm barrels, KKM and SLake, impart no dent on the frames. I did sell another mfgr's barrel because it wasn't reliable in slide action.
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