9mm versus 30 cal recoil springs

[jcoe]

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