Impact .25 700mm retuned shooting NSA 33.5 @ 915fps target.

Forums PCP Airguns Impact .25 700mm retuned shooting NSA 33.5 @ 915fps target.

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    biohazardman
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    Well after I drilled the VS out from 5.5 to 6.1mm I expected more fps but it just shoots different not better or worse.  I have a 1.25mm brass washer for a little extra hammer weight and as a spring spacer.  I also opened up the barrel port a bit probly needs dual ported, clipped the valve spring and installed a Huma reg. Oops almost forgot the Yong Heng plenum with a smallish port into the valve.  Shooting at just a bit over 150bar it used to shoot the 33.5s at 980fps on spring setting 4 now after drilling the VS out to 6.10mm with the hammer spring setting at max I get the same 980fps but with the valve adjuster turned in a turn or two if there was a line 5 it would be there. Any way not to worry it shoots good. Me not so much.  More tuning yet to come I need just a little more from the gun.

     

     

    All shots this session at 100 yards and 915fps more tuning to come.

    There is a 350 foot hill at the back of the range 200 yard marker and the wind is constantly swirling around and changing directions at 2 to about 7mph. It rarely stays the same for more than a minute or two. I am hoping to be able to deal with it someday.

     

    And if you are wondering about the short shroud it's there because I fergot that I had tucked my spare moderator away with the probe, to the barrel it belonged on, in a plastic bag inside.  So when I took it out and put it on the gun, for trouble shooting purposes, and fired it it blew the moderator apart and damaged the threads on the shroud as well. OOPS!!!  Another thought I wish I had not had.

     

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    RUisland
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    Hi, did your impact shoot the heavy's accuratly at 980fps ?

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    biohazardman
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    Only shot the NSA slugs and they were not sub moa at 980 so not good enough at that speed the target speed is 915fps. I will put that in the post thanks.  I never thought of trying the pellets I will soon. 

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    RUisland
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    Thanks for your return.

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    Skidoo165
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    I was shooting the 34 gr. Jsb's at 940 very accurate, that was about the max, anymore and the pellet got wobbly…I'm on to the slug liner now, it's a whole different animal for sure

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    biohazardman
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    Skidoo165

    I was shooting the 34 gr. Jsb's at 940 very accurate, that was about the max, anymore and the pellet got wobbly…I'm on to the slug liner now, it's a whole different animal for sure

    It looks to me like 930 – 940fps range is about where I want to be with my slugs to make my scope holdover a bit more useful at 200+ yards and still keep a decent shot count.

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