Originally Posted by Cobra

Your input pressure seems a bit low to me. On a stock impulse you should probably run your input up near 200 psi. Once you adjust the input to 200... then adjust the dwell to get the velocity you would like.

You can't go low pressure on the stock impulse very well. You really need to upgrade inorder to do that efficiently.

Also, the imp is notorious for being a gas HOG. On my stock imp I would pull around 600 shots on a 68 ci 3000.

Your best bet to improve efficiency is turn up the input pressure.

As for breakage in the barrel, that is most likely bad paint or a bad paint/barrel match. If your getting breakage on the bolt and in the chamber, that is probably chopping caused by outshooting the feedrate of your hopper. If you have vision USE IT... otherwise you will need to limit your firing rate (if that is what is causing the chops.) Otherwise (however unlikely) make sure your ball detents are compressing properly.