I know most guys are shooting the .22 slugs in the impact, but having an impact x just before the power plenum began being standard, I can only push the 29.5 flat base slugs in my .25 to the mandatory 940 FPS. I have the slug liner, and I just can't push the 32.5, 34, and heavier slugs YET. (Getting power plenum installed) These are SO accurate in my Impact that i do not mess with pellets anymore. My bro-in-law and I broke 6 oz. Jars at 280 yds!!! I'm not quite maxed out on valve adjuster, but hammer is max, and reg. pressure is on about 160. PLEASE BE AWARE!!!! THERE IS A TINY SWEET SPOT YOU HAVE TO HIT BY MAKING TINY DOWNWARD ADJUSTMENTS ON THE VALVE KNOB AFTER YOU GET THE SLUGS TO 950 FPS!!!! If you ignore this bit of mandate, you're only inviting frustration and a closet full of slug boxes. It's all about harmonics. I tried over (40) 3-shot groups of the 26.5 dish based slugs, and they simply would not group at any tune. Your mileage may vary. NICK'S CONSISTENT WEIGHT AND SIZE HAVE BEEN OUR SLUG BREAKTHROUGH!!!! THANK YOU NICK!??