I recently purchased a used Gen3 Glock 22. I have shot it on two different occassions and on both outings I had FTFs. The primers showed a divet, but the cartridge failed to fire. It happened both times after 30 rounds. Most times the cartridge would fire on a second strike. I was using Fiocchi 170gr flat nose ammo and had no issues with this ammo in my Sig P226. After the first outing I thoroughly cleaned the Upper and all parts. The Striker apprears to be un-damaged or heavily used. I also had no issues with an aftermarket 9mm conversion barrel in the same upper using Fiocchi 9mm ammo, even after the FTF with the 40s&w rounds. Any ideas for a quick fix. FYI, the gun was/is a LEO gun.