i was trying to duplicate a load I found in my Lyman manual. It called for winchester AA hulls, winchester 209 primers, WAA12r wads and 38 grains of blue dot powder, 10 O-buck for a velocity of 1375 at 9,500 psi. To start off with the lee-load-all called for a .198 powder bushing (the biggest one it comes with). I dumped ten powder loads in my scale and they averaged 35 to 36 grains. 2 to 3 grains less than what the load called for but i figured that was OK. the buckshot loaded fine but the crimps were horrible. I found if I put a BP overshot card on top of the buckshot it crimped great. My question is: will this overshot card increase the case pressure and if so how much? Will these be safe to shoot?