I recently bought a brand new Glock 17 gen 5 handgun for my recreational/conceal and home self defense handgun. The first time I shot, after 300 rounds, the trigger did not reset after the 304th shot fired. The 305th round is inside of the chamber and the slide went forward completely, but the trigger did not reset. After I dropped the mag out, pulled the slide back to eject the round, put a new mag in and pulled the slide back to chamber a round, it happened a second time after the 308th shot. After that I was able to fire hundreds of rounds with absolutely no issues. Now it only happens once every 200 to 300 rounds every time I shoot. I can then fire hundreds of rounds there after without any issues. I clean my gun after every use, and I make sure that I do not put excessive lubrication on, Glock only recommends to use lube conservatively on designated spots of the gun only, which is what I do. I also only put a needle applicant of gun oil between the trigger bar and connector, I overheard that is one of the most important spots you need to lube, with only a needle applicant use only. I have asked around at gun ranges and have spoken to the FFL dealers to get a solid answer, but I keep getting different stories and I have no idea were to start trouble shooting. I am a beginner when it comes to guns and I have little or no knowledge base. If anyone has had a similar or same issue that can give me an answer, thank you. I have left everything stock, I did not make any modifications to the gun, I also have not stripped the gun down other than to clean it and left the lower and firing channel completely alone.