As some know, I made the decision to carry the G17. So, I have had a new Gen 3 , that came with the Gen4 mags.
My first trip out a several weeks back, I had a couple of FTFs where the round was in the chamber, but still slightly in the mag, and it was always the last round in the mag. This happened with only one mag, an older LE only mag.
I felt like it could be the mag, but also felt like it could be the new recoil spring being stiff, and needing time to loosen up to allow the slide to recoil fully to the rear, as to give it adequate return velocity to chamber.
Yesterday, I took the LE mags and shot them both without any FTFs. Problem solved. It now eats everything and works with all the magazines I have.
Accuracy is typical Glock, and everything else is typical Glock.
It does shoot a little to the left which I will remedy.
As a last not, I would add that this is the second Glock I have had that required the recoil spring to break in, and that the older magazine follower design seems to play a factor in this. The current magazines supplyed with the gun worked flawlessly from the beginning. This same thing happened with my G19, it to partially chambered the last round in my older LE mags until it had about 100 rounds thru it.
But, I now feel it's ready for EDC.