What are your Impact velocities?

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Drumsnguns

Member
Jun 14, 2016
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North Carolina, United States
I'm curious as to what other Impact owners are getting in the Velocity dept. My gun came from AOA with the regulator set to 120 bar a top speeds at max and valve 4 of 795-800 fps with JSB EK Heavies 33.9gn. I reset with regulator to a gauge reading of 149 and my max now wide open is around 855-860 fps. Seems a little low from the few other reports I've seen.

Michael Wendt reports a max of 875 and Ted is reporting 862 and from his video he is shooting at PW setting of 4??? Wow!

My regulator gauge is 20-30 bar off from my bottle gauge and my bottle gauge, at 250 bar says 3150 on my supply tank and my supply tank reads 150 psi off from the dive shop gauge. So these little gauges are all kinda crappy and inaccurate. I'm pretty sure the 149 bar reading is low. But am hesitant to go over 150...even if it seems like a wrong reading.

I'd be interested to know what some of the rest of you are getting as top velocities especially with Heavies. 

Would be interesting to see....
Thanks...........
 
Hey Tom,
That thread of yours is packed full of good stuff....thanks for the effort. Wow, 25.4gn traveling at 1080fps??? I can get maybe 940? 
I guess my question and the reason for the thread is this....

Since these gauges are sooooo bad and off, I was thinking about setting it to the average hi velocity people are getting and not run the risk of hosing the regulator and voiding the warranty? Yours is set at 140 and screaming....mine is at 149 and barely on the outskirts of a respectable velocity. I know velocity isn't what we go for for accuracy but it's good to have a little in reserve.

Would you say 870-880 fps with 33.9gn Heavies, set at max everything, would be a good target velocity. That would mean I go over the 150 mark on the regulator gauge but I believe it to be low reading anyway. If it is reading +/- 5% then it could be as low as 142bar and I think that even if it was 142 it seems a bit anemic.

Any input is appreciated. BTW I have readjusted the power wheel screw and taken out the slack. It came from AOA where the slack was like setting 3 while on max. It has been loc-tited.

KP
 
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825 avg with JSB King Heavies, factory set "reg-reading" 130, power wheel set at "MAX", everything as it came from factory.
It starts coming off the reg when the bottle gauge reads 150, and the bottle gauge reads 230 when the Hill pump reaches 250. At this point lots of variables need to be sorted out regarding which gauges to believe. All I know for now is the chronograph is one I trust.
 
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Drum, I have an Impact .30. My reg is set @ 150 bar. Hammer is set @ MAX. I shoot JSB 44.75 gr Diabolo Domed. My Chony says I'm averaging 879.6 fps @ 76.88 ft-lb. I hope you can convert metrics to your .25 cal. It does sound like your numbers are a little whackadoo, though. But that's the beauty of the Impact; the adjustment options are virtually endless! I have not touched the factory settings though, and I'm pleased as punch :)! She's a hammer, alright!
 
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Ziabeam....exactly my point....not going to trust the gauges at all....but the chrony....yes. Just want to get some numbers in from you guys. Yours sounds like mine. When mine read 150 off the bottle, the regulator read 120. But the bottle reads 250 when my tank reads 3150 psi and 250 bar is 3626 psi so it's all reading low. 

Marcella...sounds like you are sitting good with your .30 Glad you got a good one! Not sure how to convert to .25. Yours has different probe so too many variables.
KP
 
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The last time my Impact was shot is was by Ernest Rowe right after he performed a tuning job on it. He set the regulator at 135 bar. and here's a pic of the shot string using 25g JSB's...

I don't know what the power wheel or return level is set at because I didn't look at it. I can look and let you know in a day or two when I get near the rifle again. 

I do recall that when I was originally going for highest velocity with the .30's, my reg was LOW! VERY LOW! My hammer was maxed and my return level was in a position I would not recommend. 
I was always happy with the 150 setting from the factory. Ernest has probably done more testing than I have at this point so, I'll trust his judgement. Whoever buys it from me can adjust it if they want to. 
As Frederik says - "There's a battle going on inside each rifle." The hammer wants to pound the heck out of the valve, the valve return spring wants to keep the valve where it is, the pressure from the bottle wants to escape anywhere it can, the regulator wants to only let so much pressure through, and on and on... You have to find the settings where everything gets along as best as it can. Then, your ES will shrink, your SD will shrink, and your smile will grow because your gun is getting along with itself. 
Remember too, that speed isn't everything. Yeah, I can cannon the 25's over 1000fps but they're going to destabilize and my groups are going to open up. Also, my rifle's probably going to be working at it's max potential so, it's not going to be very happy. 

Where is your return level set at? I'd set it at around 3.5 and see what happens. Then adjust your power level until you get close to your desired velocity. Hopefully you end up at level 4-5. Regardless, once you get close, adjust your return level until you achieve your desired velocity. Runs string to check your consistency. 
Another way to tell where your reg is set is to shoot a string. You don't have to start at full either. Start around 160 and start shooting. Your fps will possibly rise and then fall or just start to fall. Watch for this and when it happens, look at your gauge that's your reg setting. Your gauges are off - ok. Then, watch your fill system gauge and listen. You'll hear the one way valve "click" open when the pressure in the fill line overcomes the pressure in the bottle. That's pretty close to your reg setting, if you shot like I mentioned above.
If you want to double check this reading.... When you do hear the "click" close the fill valve and let things settle. Drain just a little air out of your line and go for filling again. You'll get the "click" again and be able to confirm your pressure reading. It'll be a little higher than the first time so, guesstimate some pressure off. 
At this point you've got a pretty good idea at what the reg gauge SHOULD be reading. I would simply jot that down or commit it to memory. "My reg gauge is reading ~ +10 bar."
I know you said this gauge is reading different from that one which is reading different from this 3rd one thats reading different from all of them... in so many words, lol. Go with the gauge you trust the most and work out the mathematics back to the gauge on the rifle. 
I can tell you've read some of my comments. "It has been loc-tited." LOL 
That one really messed with my head until I found it. :)
Tom
 
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Yeah, Drum; I'm really pleased with my Impact .30! So far, it's as advertised. I did run into some unexpected issues with the .30 cal. per se, though. For the life of me, I can't find lead-free .30 cal. pellets. I'm dead in the water as far as legal hunting in CA until I do so. I can't even find the type of lead pellets that fit in my mag I liked to shoot in my P-Rod and Pulsar (PolyMags and Hunter Extremes). Having said that, the JSB Diabolo Domed shoot like a dream as far as reliability and accuracy goes. Oh, well; as Roseanne Rosannadanna says, "It's always something!"
 
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Tom,

I went out this morning and worked on some of your suggestions. I elected to get Kings (25.4) down around 888 fps which is where Ernest was tuning a lot of Cricket .25's a while back. Thought that would be a good starting point. So I wound up with the Power Wheel at 2 and the valve (which I think you are referring to as the Return Level) at what I would guess to be around 3.8. You can just see the leading edge of the 4th line.
I chrony'd and got these results:
10 shots
Hi: 888
Lo: 883
Ave: 886
ES: 5
SD: 1 

What was that you were saying about the big smile? Man Those are beautiful numbers! The Heavies come in at around 825 and a quick target confirmed that they do better traveling a little slower.....at least in this gun. I'm shooting those on Power Wheel 4 and the valve at the same setting as the Kings.

Shot a couple of targets 50 yards after zeroing at 30 and both were 10 shot 1/2" groups. Well one was a smidge over and I think that was me rushing to beat the sunset.
100 yard group was rushed but out of 15 shots, 12 went into one hole measuring 1.5" 

One weird thing I've noticed and I read that someone else had this problem. When you first fire the rifle or fire it after a 10+ minute rest, the first shot is about 20fps slower and POI of course is lower. So, until I figure it out, I'm just going to fire off the first shot. I mainly target shoot but if I was an avid hunter this would get old quick!

Thanks for the number and advice. Hope this isn't a fluke and continues to shoot this good. I'll look at the regulator next but I hesitate to mess with it now.
Thanks again
KP
 
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@Drumsnguns Man, I'm stoked for your results! :D 
Do yourself a favor, take pictures of all your settings and write them down somewhere. Granted, it's only 10 shots but, an SD of 1 with .25g ammo! Wow! 
The return level knob should have slots molded into it. Those slots are different lengths so that you can accurately fine tune your settings. When I find a nice combination like you have, I use my calipers to take a measurement. 
I'd kick those heavies up about 40fps +/-. That might be as easy as 1 power level up for you. 
Tom
 
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Yeah, Tom, like I said, hope it's not a fluke. I was really surprised to see those numbers. I'm finding that this gun shoots 25.4 gn Kings better then the heavies but like I've heard, Heavies are more speed finicky. More testing with that. That's a good idea using the calipers to archive the valve setting. Will do that. Thanks for the help with this. KP
 
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