ISMI Recoil Springs

[Flankenstein]

I understand this co has a pretty great reputation. That said, I've also read a number of reports that their Glock recoil springs are a little under-sprung.

Is there any truth to this?

I just ordered a 22 lb spring for my new Gen 4 G20

[sqlbullet]

In most testing the ISMI springs run about 2 lbs lighter than advertised.  Wolff springs tend to run true to rated weight.

[Flankenstein]

Thank you sir. 2 lbs is what I have read also. So my 22lb spring is more like a 20lb...As long as it keeps the slide from banging into the frame I'm good with it.

[The_Shadow]

I run a non captive Wolff Gun Springs rod and their 22lb spring, as measured at full slide retraction at lock open it measured 22 lbs 9oz  Here are my results of the measurements;

Glock 20SF spring test Wolff Gun Springs 22lb RSA installed
It takes 6lb 4oz to start the slide to move from the locked position
Full retraction at 22lb 9oz at lock open

Glock 20SF spring test Wolff Gun Springs 24lb RSA installed
It takes 7lb 6oz to start the slide to move from the locked position
Full retraction at 24lb 1oz at lock open


Glock 20Sf Factory spring test
It takes 5lb 3oz to start the slide to move from the locked position
Full retraction at 18lb 0oz at lock open