NY1 in my G21sf and G23

[jsdintexas]

I installed a NY1 in my G23 and it works fine. Then put one in my G21sf and it does not seem to seat correctly and causes the slide to lock up about 1" backwards when trying to cycle it. Had a devil of a time getting the slide off and it appears the NY1 is riding high in the slot.
Does the NY1 not work in the G21sf or also the G30sf?

[JR]

Do not install a NY trigger spring in an SF model Glock. The problem is with the trigger housing. The SF models have a new style trigger housing that is not compatible to use with the NY spring.