Well I just pulled out my m98 from the closet. I gassed it up with co2. When I fire, it works perfectly. Then I fire a second time. It uses no co2 for this one, the bolt just goes forward. It also uncocks. When I cock it again and fire, it works. Then, again, it won't use co2 for the second shot. I took of my co2 and put in my hpa. It worked perfectly. I shot 20 times without anything bad happening. Does anyone have an idea about what is wrong?