Has anyone chronographed extra heavy weight .22 pellets in the Impact to see if they can be driven up to 1000 fps, i.e. the pile driver, rabbit magnum, ect? The pile driver ( H&N ? ) has an excellent BC. If it can be driven to 900-1000 fps, fit into the magazine and be accurate it just might make an excellent hunting pellet. I managed to get an Impact and a used scope but the chronograph is out of reach at present.
Max .22 pellet weight used in the impact at 900+ fps
- Thread starter GBGUNNER
- Start date
I would be getting a chronograph ASAP with an Impact. You will need it. Also try the JSB Jumbo Monsters 25.39 grain. They tend to work better at higher velocity's if you have a gun that can push them fast enough. I would think the Impact should be able to. Though it may need the barrel port opened up a bit to allow enough air flow. I don't have one so I'm just speculating on that point. Good luck!
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I pushed the .30 cal JSB's to
50.15gr, 887max, 878av, 7.6sd (87.63fpe)
44.75gr, 927max, 916av, 9.3sd (85.41fpe)
The 25 cal 25.4gr maxed out at 1080fps (65.8fpe)
I haven't had a chance to play around with any .22cal but, if I can push the 25.4gr out at 1080 then I'd say it's a pretty good bet.
It's all a matter of settings and air consumption. I got those speeds out of the .30 cals by opening up the valve return all the way and maxing out the power wheel (I wouldn't recommend touching the regulator. It's set to a very nice level from the factory and in this case it was actually turned down.) It was NOT air friendly when I did this! I was wasting air like crazy but I just wanted to see how fast I could get them.
The 25cal is a more accurate representation of what to expect within "normal" settings. I can't find what my settings were for that but, I do have a 1065fps jotted down as Power MAX, Level 4 (.415"). This also sent the 34gr's out at 880.
When you open up that return valve adjustment you waste more air, but your speeds go up.
Be careful crossing over 1000fps. If you break the sound barrier your pellets will de-stabilize. You'll have to google what the sound barrier is at your elevation and environmental conditions.
Happy Shooting,
Tom
P.S.
If you're going to start making adjustments to your Impact - Start a journal! Mark/write down all your factory settings.
Definitely get a good chrony setup.
Actually, just go here. There's a lot of information there and here's some tips for Impact owners.
50.15gr, 887max, 878av, 7.6sd (87.63fpe)
44.75gr, 927max, 916av, 9.3sd (85.41fpe)
The 25 cal 25.4gr maxed out at 1080fps (65.8fpe)
I haven't had a chance to play around with any .22cal but, if I can push the 25.4gr out at 1080 then I'd say it's a pretty good bet.
It's all a matter of settings and air consumption. I got those speeds out of the .30 cals by opening up the valve return all the way and maxing out the power wheel (I wouldn't recommend touching the regulator. It's set to a very nice level from the factory and in this case it was actually turned down.) It was NOT air friendly when I did this! I was wasting air like crazy but I just wanted to see how fast I could get them.
The 25cal is a more accurate representation of what to expect within "normal" settings. I can't find what my settings were for that but, I do have a 1065fps jotted down as Power MAX, Level 4 (.415"). This also sent the 34gr's out at 880.
When you open up that return valve adjustment you waste more air, but your speeds go up.
Be careful crossing over 1000fps. If you break the sound barrier your pellets will de-stabilize. You'll have to google what the sound barrier is at your elevation and environmental conditions.
Happy Shooting,
Tom
P.S.
If you're going to start making adjustments to your Impact - Start a journal! Mark/write down all your factory settings.
Definitely get a good chrony setup.
Actually, just go here. There's a lot of information there and here's some tips for Impact owners.
Upvote 0
Tominco,
Exactly what is "opened all the way up" , with my valve 1 full turn beyond the 4th hash mark my impact will not push a .25 JSB 25.39 past 970 fps. It doesn't shoot well at that speed anyway, but when I do bump up to .30 I may be looking at some anemic numbers. All of my settings are; 150 on the reg, full 250 fill, power wheel max with the slack removed, valve 4+1turn. At those same settings the heavies are launching at 870, which seems to be much closer in alignment with what you have posted. I just went out and shot to verify these numbers. Are you absolutely sure about those .25 cal. 25.39s are launching at 1080? Is your gun modified beyond stock or do feel your results would be "typical" or "common" amongst all impacts?
Exactly what is "opened all the way up" , with my valve 1 full turn beyond the 4th hash mark my impact will not push a .25 JSB 25.39 past 970 fps. It doesn't shoot well at that speed anyway, but when I do bump up to .30 I may be looking at some anemic numbers. All of my settings are; 150 on the reg, full 250 fill, power wheel max with the slack removed, valve 4+1turn. At those same settings the heavies are launching at 870, which seems to be much closer in alignment with what you have posted. I just went out and shot to verify these numbers. Are you absolutely sure about those .25 cal. 25.39s are launching at 1080? Is your gun modified beyond stock or do feel your results would be "typical" or "common" amongst all impacts?
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"Exactly" is hard to define as it was a long time ago. Remember that 1080 was MAX speed so, it most likely happened only one time (record setter). I would expect an average to be around 1065 (Max + L4) That's what I got on 11/11/15 (probably only 3-5 shots then I went to a different setting and did another 3-5, and so on, and so on.) I don't recall if I took the slack out or not when I went for these numbers. Sorry - again it was a while ago.
I'll put this out there but please understand - I don't recommend it, and am not going to be held responsible if you break your rifle, void warranty, etc... I've had my valve return 4 turns beyond the 4th hash. I was never worried about a warranty with mine so, I just dove right in head first. LOL. Basically, I backed it out until I started getting nervous it would fall off or do something that would require sending it in for repair.
To my knowledge, no modifications were ever performed to my rifle. With that being said, I have noticed that it has always shot just a bit on the hot side.
Other notes from my journal...
10/16/15 Baseline strings
.25cal
25.4 = 978 (Max + 4)
25.4 = 904.2 (Power 4 + 3)
34gr = 883 (Max + 4)
.30cal
44gr = 887
50gr = 857
Notes from Michaels chart
25cal
25.4 = 970 (Max + 4)
34gr = 875 (Max + 4)
30cal
44.7gr = 870 (Max + 4)
50gr = 840 (Max + 4)
Tom
Remember that 1080 was MAX speed so, it most likely happened only one time (record setter). I would expect an average to be around 1065 (Max + L4) That's what I got on 11/11/15 (probably only 3-5 shots then I went to a different setting and did another 3-5, and so on, and so on.) I don't recall if I took the slack out or not when I went for these numbers. Sorry - again it was a while ago. I'll put this out there but please understand - I don't recommend it, and am not going to be held responsible if you break your rifle, void warranty, etc... I've had my valve return 4 turns beyond the 4th hash. I was never worried about a warranty with mine so, I just dove right in head first. LOL. Basically, I backed it out until I started getting nervous it would fall off or do something that would require sending it in for repair.
To my knowledge, no modifications were ever performed to my rifle. With that being said, I have noticed that it has always shot just a bit on the hot side.
Other notes from my journal...
10/16/15 Baseline strings
.25cal
25.4 = 978 (Max + 4)
25.4 = 904.2 (Power 4 + 3)
34gr = 883 (Max + 4)
.30cal
44gr = 887
50gr = 857
Notes from Michaels chart
25cal
25.4 = 970 (Max + 4)
34gr = 875 (Max + 4)
30cal
44.7gr = 870 (Max + 4)
50gr = 840 (Max + 4)
Tom
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TO you who responded to my query about heavy .22 pellets. I find conflicting info....Ted's review of the impact suggests valve set at 4 hash marks and power wheel at 4 for .25 34 gr JSB & 3 for .25 for 25gr JSB for good accuracy. I fired my .25 impact at max with 25 gr JSB and the pellet key holed the target at 20 yards. I had been shooting at 3 power as I'm in the yard. Michael's chart indicated .25 25gr JSB - valve at 3 hash marks and max power wheel was about 950 fpsI need to do more shooting at varying known distances to get more info. Could have been a bad pellet. I'm looking to get a .22 barrel for my impact and was wondering about the piledriver pellet in particular as it seems to have the highest ballistic coefficient. If it can be driven to 960/1000 fps and is accurate it might make a long distance hunting pellet. Has anyone tried this combonation?
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GBGUNNER,
Sorry we got off topic a little there. I wish I had some piledrivers, I'd do a test for you in a heartbeat! All I can really say is, from what I've read over the years, the opinion is that smooth twist barrels tend to shoot the most stable pellet at around 880-910 fps. Faster is not necessarily always better. But, I get what you're saying about the coefficient. Still, I think it can be done with the Impact with a little tuning. I think the best bet is to borrow/buy a chrony and go from there.
I'd start at MAX + 4 and see where you're at and then back out the valve return knob in 1/2 turn increments until you get to that 1000.
FYI, my Impact shoots its most consistent strings at power 4, like Ted mentioned.
If you want to send me some piledrivers, I'd be happy to see what I can come up with. As far as fitting into the magazine, I have no idea. Have you read of any issues fitting piledrivers into standard (smaller) FX magazines? The Impact mags are the same thickness so, that could be a way to answer your question.
Tom
Sorry we got off topic a little there. I wish I had some piledrivers, I'd do a test for you in a heartbeat! All I can really say is, from what I've read over the years, the opinion is that smooth twist barrels tend to shoot the most stable pellet at around 880-910 fps. Faster is not necessarily always better. But, I get what you're saying about the coefficient. Still, I think it can be done with the Impact with a little tuning. I think the best bet is to borrow/buy a chrony and go from there.
I'd start at MAX + 4 and see where you're at and then back out the valve return knob in 1/2 turn increments until you get to that 1000.
FYI, my Impact shoots its most consistent strings at power 4, like Ted mentioned.
If you want to send me some piledrivers, I'd be happy to see what I can come up with. As far as fitting into the magazine, I have no idea. Have you read of any issues fitting piledrivers into standard (smaller) FX magazines? The Impact mags are the same thickness so, that could be a way to answer your question.
Tom
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Thanks Tom, I had thought to try and drive them at 900 to 1000 and test for accuracy would be the best approach I appreciate and enjoyed the response to my question and everything that was discussed and re read all off it, yours twice and got what you were saying, which I also believe. I'm in catch 22. $500 for a .22 barrel kit for the Impact to test pellets I don't have with a chronograph I can't afford yet. Think my best bet it to acquire the pellets in question and see if the cadwell $90 chronograph is worth having and see what kind of accuracy and expansion I get from these pellets with a FX Bobcat I think I can borrow. If that goes well perhaps I could send you pellets to chronograph and check for accuracy with the Impact in .22. Then we would all share the information and I could decide on a .22 barrel kit for my Impact would be worth it or to look into the .30 . At present I hope the .22 will prove out. Any experience with the cadwell chronie with the IR light bar on amazon. I've a short range in the basement when I include the crawl space for testing. Thanks guys for your responces. GBGUNNER
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