9mm versus 30 cal recoil springs
 

Is there such a thing as a 30 cal luger spring? That is less robust than the 9 mm spring? And is there an easy way to identify this 30 cal spring from a 9 mm spring? My problem is with an 8 inch 30 cal luger barrel mounted on a 9mm receiver/frame; the mag feeding difficulty suggests that the recoil spring is too strong and does not allow full extension/recoil of the toggle. Any suggestions? Or do you use the empirical approach and sequentially clip coils until feeding is correct?
John

In places that I have seen replacement springs for Lugers, I have not yet seen one that indicates for a .30 or 9mm. Based on that I would say no.

As an interesting point, the SIG 210 series have different springs for the two calibers: .30 luger and 9mm. The .30 luger spring is the weaker of the two.

jcoe et al, The original DWM 7.65mm recoil spring only has 17 coils, whereas their 9mm has 19. The Mauser 9mm springs usually have 21 turns, so they could handle the hotter SMG rounds. TH

Thanks gentlemen, and especial thanks to Tom for his 17,19,21 information.
I will do some counting.
John