i have shot about 80 rounds or so with my mk 85 using 120 gr of 777 and a 300gr bullet,i use the cci 209 primer to set it off. It kicks but i have got very good results using this load it holds true out to about 90 yards before it starts to drop. And i am getting complete passthrough shots on deer and hogs at a 100 yards. I shot a big doe tuesday at 137 yards i held 2 inches high on her back and the bullet hit right below the backbone. After the season ends i am going to try a new bullet its just a tad smaller and i am going to start the 777 at a 100gr and work around that till i get it right.