So I figured out my hammer spring adjustment on my Sniper XR. I cranked it up almost as high as it can go. I’m looking to shoot the 20.3 gr Howler slugs out of it at distances out to 100 yards or so. TP is on the highest setting and I have the reg set at 145 BAR. But it only shoots these (lightweight) slugs at 790 fps…….barely 28 foot/pounds. Is that all this gun can do, or am I missing something?