Hello fellow shooters,
It seems these guns are very different as far as power output, (velocity), is concerned. All velocities were made with all the slack taken out of the hammer adjuster and the power wheel is on max. With the stock parts the reg. tops out at 120 bars. Anything over that doesn't increase velocity and after about 125-130 bars the velocity goes down. The velocity with the jsb 34 gr. tops out at 923 fps. I was informed by FXUSA that by changing the hammer spring and valve spring the gun should shoot the 34gr. up to around 1000 fps.The hammer spring was then changed from 52 to 57mm and a lighter valve spring was installed. The gun shot exactly the same like nothing was done. Not knowing for sure how far the valve was opening I did the following. A .200" stop was made out of delrin and placed in the valve adjuster cap. The cap was then screwed in until the stop made contact with the end of the valve rod. I continued to turn the cap until the valve was completely closed. Then a measurement was taken from the end of the cap to the shoulder of valve adjuster housing. Then I unscrewed the cap .100",.150", and .200''. I then put in a very lite valve spring. The purpose of all this was to make sure the valve was opening and how far. Each setting was tested at 120, 130, and 140 bars. I could see that the end of the valve rod was touching my delrin stop so I knew that the valve was opening to whatever I had it set at. After all that the reg. toped out at 130 bars and the velocity was at 943 fps. More than 130 bars and the velocity goes down. I've spoken to Ernest about this and he was able to get 1000 fps from a stock Impact MK11 .25 cal. w/pp by changing the two springs and setting the reg. around 155 - 160 bars. All the measurements that he asked me to take are what they're suposed to be. We are lost at this point on why this gun won't generate high power. Has anyone out there had a Impact in .25 cal. that started out with low power and was able to make the necessary changes to get the power up? The gun was bought specifically to shoot the heavier pellets/slugs between 900 - 1000 fps. I been told that the superior liners will be back in stock very soon. The gun has the stock pellet STX liner. The goal is to try out several slugs at velocities over 900 fps. I've done some testing with a RAW HM1000X poly under 900 fps with poor results. I know shooting slugs in .25 cal. is tough if you want 1 moa at 100yds. All one can do is try. Thank you.
in the velocity
It seems these guns are very different as far as power output, (velocity), is concerned. All velocities were made with all the slack taken out of the hammer adjuster and the power wheel is on max. With the stock parts the reg. tops out at 120 bars. Anything over that doesn't increase velocity and after about 125-130 bars the velocity goes down. The velocity with the jsb 34 gr. tops out at 923 fps. I was informed by FXUSA that by changing the hammer spring and valve spring the gun should shoot the 34gr. up to around 1000 fps.The hammer spring was then changed from 52 to 57mm and a lighter valve spring was installed. The gun shot exactly the same like nothing was done. Not knowing for sure how far the valve was opening I did the following. A .200" stop was made out of delrin and placed in the valve adjuster cap. The cap was then screwed in until the stop made contact with the end of the valve rod. I continued to turn the cap until the valve was completely closed. Then a measurement was taken from the end of the cap to the shoulder of valve adjuster housing. Then I unscrewed the cap .100",.150", and .200''. I then put in a very lite valve spring. The purpose of all this was to make sure the valve was opening and how far. Each setting was tested at 120, 130, and 140 bars. I could see that the end of the valve rod was touching my delrin stop so I knew that the valve was opening to whatever I had it set at. After all that the reg. toped out at 130 bars and the velocity was at 943 fps. More than 130 bars and the velocity goes down. I've spoken to Ernest about this and he was able to get 1000 fps from a stock Impact MK11 .25 cal. w/pp by changing the two springs and setting the reg. around 155 - 160 bars. All the measurements that he asked me to take are what they're suposed to be. We are lost at this point on why this gun won't generate high power. Has anyone out there had a Impact in .25 cal. that started out with low power and was able to make the necessary changes to get the power up? The gun was bought specifically to shoot the heavier pellets/slugs between 900 - 1000 fps. I been told that the superior liners will be back in stock very soon. The gun has the stock pellet STX liner. The goal is to try out several slugs at velocities over 900 fps. I've done some testing with a RAW HM1000X poly under 900 fps with poor results. I know shooting slugs in .25 cal. is tough if you want 1 moa at 100yds. All one can do is try. Thank you.
in the velocity
