If I were going to try to use the original cases, I would pop as many as would fire in my rifle and junk the rest. You can buy a Berdan decapping tool from RCBS or use a very sharp awl or ice pick to pry out the spent primers. You can decap both live and spent primers using hydraulics, but I haven't had much luck doing it that way. The real problem is going to be locating the primers. Old West Scrounger used to carry RWS primers, but they were over twice as expensive as Boxer primers. I figured out that I could buy 100 Boxer cases and 1000 Boxer primers and still be ahead of the game. PMC was importing Russian-made Berdan primers for a short time, then stopped. I never saw any locally and tried to get local reps to order them without success. Someone else on the boards might know something I don't, however. Also, don't forget that the standard Berdan primer is larger than the .217" large Boxer primer and you might have to modify your priming tool slightly to accomodate it. Check your firing pin spring; it may be a little weak. I replaced mine with a 21-lb. spring and that really improved matters. If your Czech ammo is like the stuff I used to have, it had some really hard primers. One more thing to check: The 1950's Czech I had was loaded with their copy of the German S.m.E., a 181-gr. boat-tailed steel core bullet.