Just received my new Impact with Power Plenum

Forums PCP Airguns Just received my new Impact with Power Plenum

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    drumie
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    I just wanted to do a quick update. I just received my new Impact 30 cal with the power plenum.  I haven't had a chance to really test it out yet. Just doing some chrony work on it inside.  This is what I am seeing so far.

    JSB 44 gr.  reg set at 150psi the highest speed I could get here was right at 860fps.  If I turned the reg up the speed dropped.  I thought these came with a heavier hammer so this wouldn't have been a issue.  I thought that the power wheel was almost maxed out, but after checking I had some more room to turn it in.

    After I opened up the transferport and the pellet probe, the gun would not load pellets.  I did the half moon on the probe, like I have on my 22 and 25 cal impacts, the 30 cal would not feed straight.  I had 2 probes like that and neither would feed right.  When I put a stock one back in it feed fine. I also checked and was able to get almost a full turn on the power wheel bolt. After doing that mod I was trying the Nielson 49gr slugs. Those where shooting 920fps.  That is 92 FPE. Those are some good numbers.  Hopefully I can get a little more power out of this with some more tuning. What I plan on doing is cutting the end off of one of the probes and drilling and tapping the end. Getting a rod that has some threads on the end and using that as a new probe end.  I don't have access to a lath so I will give that a try for now. 

    I will give more updates when I get a chance to go out and shoot it and try some more stuff with it.  I only got this gun 2 days ago so I haven't had much time to play with it yet.

     

    • This topic was modified 1 month ago by drumie.
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    heavy-impact
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    Could you post a picture of your modified probe and maybe we can diagnose the feeding problem.

    • This reply was modified 1 month ago by a Moderator.
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    Glem.Chally
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    I dont think its worth porting much in .30 as its basically bore size anyways.  Try lowering the reg to 120 or so and see what happens.  Valve adjuster was all the way out for your testing?

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    drumie
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    The valve adjuster was all the way out.  I will post a pic of the probe tomorrow, my phone is down and i need to get it fixed before I can post some pics.

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    Mikepr
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    150 bar with 64 cc plenum is a lot of pressure behind the hammer
    Try less pressure

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    heavy-impact
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    Mikepr

    150 bar with 64 cc plenum is a lot of pressure behind the hammer
    Try less pressure

    The FX version is 60cc but has no bearing on the force it takes to open the valve. Pressure and valve area determine that.

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    Hande
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    sniperlabyo
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    Best performance is around 135-143b if you go above speed will settle, if you raise about 155 speed will drop no matter if you adjust the HS preload to max or valve adjuster pass oring groove. Wasn’t designed above 145b. Another mods/tunes can be performed to increase speed. When tuned the max speed with .30 50gn JSB 700mm is on or about 100FPE. On .30 are more subject to jamming when Over Enlarging either Transfer port. This double design TP has a bridge in the middle so the ammo will never drop in the TP.

     

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    heavy-impact
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    Hande

    Thanks for the correction. I've seen some conflicting information on FX's version.

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    jwrabbit123
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    so Ernest is saying , if you raise reg with new plenum dont go pas 143 bar and sweet spot is between 138 bar to 143 bar , I believe hes saying when you went to 150 the hammer is not opening the valve fully , and the bottle nect is flow in transfer port and probe , where you can get more power but got to be careful , I think the guys who shooting them really hi power change springs and hammer weights , but they you can suffer from shot count and accuracy .

     

    I can say since I had an impact in early 2016 , they really came along way with people here and FX and Ernest coming up with new designs , I  like the new impact alot , I am thinking of adding one again to my collection , If I do it will be 25 caliber . This is the only caliber I am lacking a good slug gun

                                                                                      LOU

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    Bushwackert
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    With Power Plenum and the reg set around 145 bar you should be able to get 950 fps with the 45gr JSB and 930 with the 47gr NSA slugs with the default .30 TP and probe.

    Just make sure the hammer spring is maxed out on the Max power wheel setting, there's usually a lot of wiggle room here when fresh from factory.

     

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    GQ
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    Rewind your fine tuning procedure.

    Start with your regulator set to 120 bar and proceed step by step.

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    MonsterMaxx
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    Thumper is hitting right at 100FPE w/ the 50gr JSB

    The 44.75 is flying over 1000fps.

    reg set at 155b

    Accuracy is garbage past 50yds.

    So I turned everything down in little steps, long story short, much better accuracy.

    Now it's at 110b, 44.75 JSB, 880fps and I think the accuracy has come back quite well.
    5 shots @ 85yds

     

    I've got a 700mm and slug liner coming from Utah, see if we can do better :D

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    GQ
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    MonsterMaxx

    Thumper is hitting right at 100FPE w/ the 50gr JSB

    The 44.75 is flying over 1000fps.

    reg set at 155b

    Accuracy is garbage past 50yds.

    So I turned everything down in little steps, long story short, much better accuracy.

    Now it's at 110b, 44.75 JSB, 880fps and I think the accuracy has come back quite well.
    5 shots @ 85yds

     

    I've got a 700mm and slug liner coming from Utah, see if we can do better :D

    Your Impact seems to be the first generation if i am not wrong.

    How did you get your regulator up to 155 bars ?

     

     

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    drumie
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    Well I had a few minutes yesterday to tinker with my Impact.  I turned down the reg to just over 140psi, power wheel maxed out but just free enough to turn. Shooting the 44gr JSB got me 930. The Nielson 49gr were right at 920. One thing I did find is the JSB do not load well from the magazine.  I tried 3 different mags and they all would hang up. The Nielson loaded very smoothly.  Not a issue for me as I plan on only shooting slugs with this. 

    Here is a pic of the mod I did to the probe. It would not load slugs or pellets. 

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