I just bought my wife a used Glock 19 and took it to the range today. The 10th round was a misfire. There was no primer mark anywhere on the cartridge, i ejected the round, reloaded it and fired through 100 rounds without any issues. The gun was clean, i cant see any obvious defects at all. Anyone ever had an issue like this? Could it be something as simple as springs? Any input is appreciated.