I just gave a quick look into my Luger parts bin, and found three new Wolff recoil springs in the shrinkwrap...All three seem to be the same length and number of coils...Only difference is the wire diameter (which is good)...
36# - .056" dia
38# - .057" "
40# - .058" "
I thought they offered a "Pak" with all three, but mine are individual...
I haven't had to use them, as I handload...I select a bullet type & weight, and brand of powder...and then load the minimum amount of powder for that bullet...and increase it by one-half grain until the pistol ejects & feeds reliably...
Saves money on new springs...