It looks like there is 1 more left int he chamber at the end.
I remeber playing Syphon Filter on PS1 and shooting with the G18 and thinking to myself, this thing would be kickass to fire in real life, an indeed it looks like it. It's nice have a supply of 400 rounds in the game though.
Is it the Glock or Beretta that has a shoulder stock attachment that turns it to full auto, I think it was the Glock so that means he did the conversion himself which explains the jamming, but that means there is hope for us (those who want one)yet!