Okay so I’m about to be the proud new owner of an Impact X so of course, my YouTube search bar is full trying to find out how to tune this gun! But my question is, every video says tune until you’ve reached “desired velocity” for that pellet, what is this Velocity? What velocities have you found work well with STX/JSB combo? In both .25 grain weights
JSB pellets FX impact
- Thread starter Kerbow01
- Start date
most fx guns are set up to shoot jsb pellets around 900fps more or less that seems to be the case with both my rifles bobcat and impact and friends that have wildcat and streamline are the same fps. The trick with the impact it getting all 3 settings ballanced,regulator,hammer spring, and valve spring. I shoot the heavys with incredable accuracy at these velocity's. Congadulations on a world class airgun!
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Ordered an Impact X 700mm as well, UPS said it should arrive tomorrow 
, can't wait. Have been ordering tons of accessories on amazon & eBay, each day is like Xmas. I too have been googling info on best pellets, weights, and velocity.
Look at the information in this link: https://hardairmagazine.com/ballistic-coefficients/
Has some great info.
Congrats!
, can't wait. Have been ordering tons of accessories on amazon & eBay, each day is like Xmas. I too have been googling info on best pellets, weights, and velocity. Look at the information in this link: https://hardairmagazine.com/ballistic-coefficients/
Has some great info.
Congrats!
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You'll need to get a chronograph to tune your impact. When I first got my impact it was tuned to shoot jsb 25.39 at 910 fps. I wanted to shoot the heavier jsb 33.95 mk2 but I needed a chronograph to tune it, I have it tuned to shoot at 880 fps. Check out youtube and guys like Steve and Matt have videos on tuning.
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Listen good to Steve from AEAC, because he had it right. JSB in STX barrel, 860 feet per second. Try it, it will be the best. Slower or faster and it will spiral. Keep it at 860 plus or minus a few feet. At 110 yard I get 1 big hole. If I am not at 860 feet/second, the group opens up tremendously.
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Before getting too excited and messing with the settings, Impacts come from the factory tuned to shoot a specific pellet. In .25 that is the JSB 25.39s. Unless you don't want to shoot those pellets, or you're really looking to play around at the bleeding edge of performance, my advice is that you simply don't mess with it...... for a while at least. Just enjoy and shoot the gun a bit. If there is a problem it is easy to tweak, but that certainly doesn't mean you have to.
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Funny how velocity effects pellets. I have found that when i hit different speeds the accuracy comes and go's.for instance with my .25 Impact at around 860 the heavy's shoot well then accuracy drops till around 880 and again it puts pellets in the same hole.I also found that speed isn't the only thing determines accuracy, Its a balance between reg pressure hammer spring tension and valve spring adjustment a harmony sort of speak .I'm posting my best 5 shot group just to show the rifles capability 
.5 shots 58yrds JSB Heavy's Enjoy your new rifles guys i love mine.
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I'm shooting a .30 but anything from 800 to 950 with JSB works well. I've got it right at 950 now for the 44.75 and it stills groups tight. Most of my shots are under 75 yds.
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Yeah i really want to shoot the Heavies and also get the most out of the gun. I do A LOT of long range hunting. Mostly pigeons from 75-125 yards. That being said i really want the gun to be performing at its peak at these distances to serve a quick clean kill. So right now I’m seeing the prime velocity to shoot for while tuning will be between 860-880 give or take a little. Or this is where i plan to start at least.
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