Don't shoot the load out with cap and powder....you have a brass and steel screw stuck in the projectile. either use a co2 system to shoot it out, or make a simple adapter (male thread on one end to fit the vent, and female thread on the other to fit a grease zerk - a drilled out spare nipple and some rubber hose and good but smallish hose clamps will likely work or thread or even solder same up to some copper or steel tubing ) and use a grease gun to pump out the entire load, powder/bullet/screw and all.