Recoil springs and lockup

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Finally got my spring measuring technique sorted out, and have some accurate measurements.

As some of you may recall, there was a discussion of firing a Luger while it was not quite in battery. The question arose using 4.6 grains of Unique behind a Speer 100 grain Plinker in my mismatched DWM with a 25.5 lbf spring. This spring has a preload of 10.2 lbf. Fiocchi factory stuff ran through OK.

With a 32.0 lbf loaded, 20.0 lbf preloaded spring, this same gun has ejection problems with Winchester ammo and Fiocchi ammo. It will sometimes rechamber the empty case with Fiocchi ammo and this spring.

The slide feels a trifle stiffer than my nickle plated shooter. Either the nickle is slicker, or the mismatch has a stiffer ejection spring.

But I think it's safe to say that a 25 lbf spring is the absolute minimum for wimpy loads. (Wimpy is a bit derogatory. They're midrange loads if you are doing serious target shooting.)

Eventually I hope to develop a formula to calculate the required spring based on the load or vice versa.

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