Very interesting. I'm not really sure. The .40 spring may be stiffer but I don't know. The only thing I can suggest is getting on a Glock parts site and see if the springs for both guns are listed under the same part #.
Just got the below items for my G22 Gen4. Can I use the stock recoil spring with no problems or do I need a G17 spring?
Yes, its a 9mm conversion barrel.
I have a Gen 3 G35 which I bought a LWD 9mm conversion barrel and I use the factory recoil spring. I think they say on Lone Wolfs web site it tells you that you might have to change the recoil spring, check there first.
I'm sort of confused because on some web sites they show the exact same part number for the Gen4 G17 and G22 spring while other ones have different ones listed. Guess I will just try it and see how it works.
I recently got a KKM conversion barrel and 9mm mag for my G22 gen4. I have never had any failures with .40cal but had lots of eject and feed issues. Part of it was probably the crappy 115gr ammo at the range, but I think there is another issue. While many claim you don't need to change the recoil spring I think you do in a gen4 gun. Glock seems to think so too. I just spoke with tech support and they told me the g17 spring and the g22 springs are different. The G22 is part number FP07577 while the G17 is FP08284. I think the G22 spring is stiffer and the light 9mm ammo does not have enough energy to fully work the slide with the stiffer spring.