Thanks to Ben Murray, I no longer have the popped primer problem. I have what was a brand new Norinco Paratrooper. In May 2012, before ever firing it, I installed his modified firing pin to eliminate any possibility of a slam fire. But, in no time, I experienced multiple popped primers using the white boxed ammo made in Russia, which some say is made by Wolf. My Paratrooper was unusable. The spring was fried and the firing pin jammed. To make a long story shorter, he worked with me over the last year looking for a cure, and I am happy to say that my Paratrooper is finally a real trooper and runs perfectly. The neck and throat reaming service works. That is what handled the popped primer problem. I am now shooting the same lot of white boxed ammo as before with no problems at all.
In addition, I've upgraded to his latest version of spring firing pin and had him install his sear and adjust my trigger. Real nice. It runs smooth as can be. I can now easily hit an 8" diameter steel target [painted red so I can see it] 200 meters away while shooting standing/freestyle with the original iron sights.