I bought a used glock 21 yesterday. I didn't clean it before heading to the range. Didn't think I had to. I went out to shoot with 2 boxes fracchi 230 grain. I had a misfire on my first mag. Bullet had a strike mark but didn't fire. I reloaded my mag and tried again. Same thing but this time it was on the last round. Long story short, the problem continued for every subsequent magazine and on the last round. Any idea what the problem is?