I bought a surplus Hi Power from a member on this site. I took it to the range today for the first time. I started with one box of blazer ammo and for several 13rd mags the pistol functioned good. But then a problem started and got worse. I would fire the pistol and the next round would camber, the hammer would cock, but then I pulled the trigger and the hammer would not drop? This started happening over and over again till I stopped and went home. At that time I was using Monarch ammo. A few times I was able to release the trigger and pull again and pistol fired. But that only worked several times. Anybody have an idea what the problem is?