Rimfire22 wrote:Hi, hoping to find out some info about a rifle I have put together, Sportco model 90 pump action .22. It had an ejection prob, but I have fixed this. It cycles well but I have the odd misfire and variation in firing pin strike dent and when using high velocity bullets I have notice that the base of the case is flattened. The brand name on the base is noticeable flat. I thought the problem would be tight head spacing, but the misfire and light dents in rim tells me to much head space. I know these are not the best rifles around, but it fits in my group nicely. Any info would be great. Thanks.
Can you post photos of the brass? Is the barrel original? Could the barrel have a .22 Short or .22 Long chamber perhaps?
The light primer strikes are not necessarily indicating a headspace problem. Have you tried different brands of ammo?
I get lots more light strikes with Eley ammo than anything else as they have very thin rims.