Buster95,
A few handis do pop open immediately AFTER firing. As trotterlg said, this is not a dangerous situation. However, it is not normal and it is not supposed to do this. If you bought your handi new from the factory and it consistently pops open, you should send it back to the factory for repair. If you bought it used, you can fix it yourself with the information included in the FAQ's at the top of this forum. As singleshotsam said, it is caused by a poor latch engagement. Probably the number one reason for sporadic pop-opens is allowing excess oil and crud to build up on the barrel latch and latch shelf (I have been guilty of this at times), so first thing to try is simply giving it a good cleaning. If that doesn't help, you can work on improving the fit of the barrel to the reciever. (Again, all this info is in the FAQ's). To reassure you, most handi's do not pop open, and those that do can usually be fixed, and the factory will do this for you if its still reasonably under warranty.
Duane