I hope this is the right place to post this but I just wanted to contribute to the wealth of knowledge on this forum by giving a brief overview of my experiences with the first 500 rounds through a Gen 4 Glock 17. This is my first firearm purchase and before April it had been over 14 years since I had fired any firearm. Before I purchased the G17 I ran roughly 500 rounds through various other firearms including various 1911, gen 3 glocks, XDM, XD, SW MP and others. And at first I did not like the glocks and was heavily leaning towards the XDM. All the glocks I tried(all gen 3) just didn't sit right in my hand then I ran 100 rounds through a gen 4 g17 and was instantly sold it just felt right. So after learning that glock stopped making OD glocks which is what I wanted I found STG Firearms in Arizona and even though it took a week longer than expected I was greeted with this gorgeous piece of equitment when I went to my local range to pick it up. After filling out the forms and purchasing a 33 round mag and a membership to said local range I checked the gun for any excess grease or barrel blockages(no problems the guys at stg sent a range ready gun clean and lubricated) then I put 100 rounds of blazer 124 gr and 50 rounds of Speer lawman 115. With no problems at all. The next 150 rounds were a mix of winchester white box, blazer 115, and American eagle 115. Wasnt until round 299 ( a blazer 115) when it failed to eject the casing was back in the barrel with a small split down the casing starting at the top going down about a centimeter. during the second trip to the range I noticed that depending on how tightly I was gripping the pistol the brass would eject differenty too tight and i got hit in the face any other grip and it went to the right. The third trip was 50 rounds winchester white and 150 rounds of blazer (quick side track blazer 115 is selling for 9.99 here) on round 499(again a blazer 115) had anouther failure to eject where the casing came out and back in to the barrel. I must mention my first thoughts on the 33 round mag in a word Amazing. I couldnt believe how amazing the mag felt in the gun the added weight felt perfect anyone who owns a G17 needs a 33 round mag(sorry if you live in a state that dosnt allow it) it should come standard. In the end I feel like this gun will be with me for the rest of my life and I will enjoy every day that I am able to take it shooting. I just thought I would share my experience for anyone contimplating a gen 4 g17. I hope to keep this post updated each time I go to the range. Any questions comments or advice are appreciated especially comments on the 2 failure to eject.