I recently purchased an FX King .22 600mm barrel. I was going back and forth between the 500mm and 600mm, especially when the 600mm comes with the stx superior heavy liner. I decided on the 600mm and was hoping it would shoot slugs and heavier pellets. I didn't have any slugs so I tried some pellets. The regulator is set at 110 bar. The rifle is easy to adjust the velocity, and I made adjustments to match the optimum velocity for each pellet, 880-930 fps. The lighter pellets, 15.9 - 21.14, didn't work so well. Even at the approx optimized velocity, I would get fliers which would open up the groups at 50yds. I would get two rounds touching and then two or more 1-2" away. I finally tried some 25.4 exact jumbo monsters. After adjusting the velocity up and down, I settled on 957 fps. The gun shot very low velocity spreads, and ended up shooting some great groups. This was my first outing with the new rifle, but it looks like it will shoot the heavy pellets quite well. I will experiment more as I have ordered additional slugs and heavy pellets. At 957 fps, I was on setting 21 on the macro-adjuster and 2.25 on the micro-adjuster. I shot a total of 64 shots and was still above the regulator setting. At that velocity, with that pellet, I was getting 51 ft/lbs of energy.
I really like the airgun and the GRS stock. It is light, efficient, powerful, and easily adjustable. The GRS stock is very comfortable for me and is easily adjusted to make it fit your shooting style. I actually like the location of the pressure gauges as you can monitor your bottle pressure very easily. It is simple to adjust your velocity to match your activity whether hunting, plinking, shooting for groups, or looking for a massive shot count. Attached are the last three groups I shot with the 25.4 monsters at 50 yards. The gun seemed to be settling down and the group to the left was my last group. All are 5 shot groups.
I really like the airgun and the GRS stock. It is light, efficient, powerful, and easily adjustable. The GRS stock is very comfortable for me and is easily adjusted to make it fit your shooting style. I actually like the location of the pressure gauges as you can monitor your bottle pressure very easily. It is simple to adjust your velocity to match your activity whether hunting, plinking, shooting for groups, or looking for a massive shot count. Attached are the last three groups I shot with the 25.4 monsters at 50 yards. The gun seemed to be settling down and the group to the left was my last group. All are 5 shot groups.
