Yep got a Px4, and managed to get 3 spare mags cheap via a friend in the States. Great blowback but you are working with fixed sights. Using the lower rail you could fit a mount and a red dot. Hardly had any jams, but using the right pellets and seating them properly helps! I prefer my ASG Cz P09 but the blowback isn't as good and I have fitted a red dot sight for better accuracy.