Hey guys let me throw my 2 cents worth in this discussion. After spending some time looking at a Gen4 22 for use as a duty weapon and having one do something I felt it shouldn't while inspecting it at the local shop(no need to go into details here I already posted on it a while back) I finally decided to wait until I could meet up with the regional LE rep from Glock and ask some questions as well as test fire a few test and evaluation guns.
Not to get off-topic too much but he showed up with a trunk full of Glocks with every model known to man except the .380 and honestly I didn't ask so that may have been there too. He even brought a full auto Gen 4 G18.
Anyways he pulls a G22 box out the trunk, opens it and after removing the magazine and locking the slide back, hands me the pistol. I look and the first thing I see is the thing is filthy. When asked when was the last time it was cleaned, he just smiled at me and told me that he never cleans any of the test and evaluation guns to prove a point. According to him, not one of his test guns has ever malfunctioned. Pretty impressive right! I couldn't make them malfunction either, not that I was trying to but did shoot quite a bit of ammo on Glock's dime.
I had heard about issues with the G17 and asked him about it since there were multiple reasons we were already discussing it as a possible selection for my department. The response I received was that any cheap ammo that is loaded to minimum or close to minimum powder levels(as most cheap target ammo is) will not generate enough pressured to fully cycle the slide because the spring is designed for duty or sd ammo. However, he advised me that the problem could usually be resolved by running 100 rounds or so of +p ammo through the firearm which would break in and help loosen the stiffness of the spring.
Even so, Glock was aware of the mass of complaints and has now changed the spring that comes in the G17. If you look closely on the metal disc part of the the spring/rod assembly, you should see a number on it. I believe the new issue ones is something like 02. However, I am at work atm and will not be taking apart my duty weapon to double check. If you have a problem with your current Gen 4 G17, you should be able to contact Glock and receive this new spring/rod assembly at no charge.
Also I noticed an earlier post by a fellow LEO about his G17 issues on a duty weapon he purchased himself. According to my local Glock LE dealer, you should be able to have that firearm fixed or replaced (other then normal wear and tear) for as long as you own the firearm if you bought it through a Glock LE dealer using the LEO purchase program.
Finally (I get long winded I know hang in there), I ended up buying a Gen 4 G17 about a month ago to use as a duty weapon. At this time I am pretty darn close to 1k rounds and have not had a single issue with it. I have shot nothing but cheap target ammunition including Remington UMC, American Eagle, WBW, Zero, and some Georgia Arms. I actually took it to the academy 2 days ago and used it to shoot a qualification score for firearms instructor school(i go this week yay) and shot the absolute best score I have ever shot on that particular course in my life.
Moral of the story is check your spring/rod assembly and see which one you have. Then either try running some +p ammo through it or call Glock and get the new spring/rod assembly. From then on enjoy and be confident. It won't let you down.