This gun is new to me. I've shot a few hundred pellets so far and had a small leak out of the hole to the rear of the safety. Took it apart and found that the oring was on its last leg. Upon closer inspection I believe I found a dent in the reg piston meaning I'll have to pay as much for shipping as I will the part :/ Previous owner assured me the gun had not been adjusted in any way, so is this a dent or how the piston is supposed to look?
Fx impact reg piston question
- Thread starter Wetliknives
- Start date
The hole is supposed to be there but the center of the piston looks to have the dent. Doesnt look good man. Usaully when air comes out that hole youll have a tear on one of the oring on the reg adjuster screw. Pretty easy fix though buy new piston and o-rings i would buy 2 of each to be prepared if theres a next time.
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The small off center hole is the inlet to fill the regulated air chamber.
the center indent is the delrin seat for the adjustable screw brass seat---- that's normal unless it doesn't have a good Seal then you will have a reg creep.
one of the oring 33,35 or 39 is leaking
dont mark up the regulator rod sealing area for oring 35, some guys pull on the end to remove the rod.
the center indent is the delrin seat for the adjustable screw brass seat---- that's normal unless it doesn't have a good Seal then you will have a reg creep.
one of the oring 33,35 or 39 is leaking
dont mark up the regulator rod sealing area for oring 35, some guys pull on the end to remove the rod.
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The dent was caused by someone screwing the regulator adjustment screw in against pressure. The pressure needs to be bled before adjusting the reg down. This is expressly stated in the owners manual. The piston is toast.
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depending on the setting of the reg there is ---let say 150b forcing the piston rod against the adjustable seat to shut off the supply of air to maintain 150b so there will be an indication of contact----that what you see, unless when you reinstall the brass adjustable screw and force it on the rod and made a deep indent, I lightly bottom it out then CCW 1.5 tunes to set the pressure around 120b, when pressured you can fine tune the pressure up
check for creep in hours of idle or next day, 5b increase is normal. if reg gauge equalized with bottle pressure or 10b + diff the rod piston sealing surface need a light resurfacing on a lathe---but 1st you need to replace the closest 1X2mm oring to the piston on the adjustable screw, if that is leaking it will pressurized the reg chamber also.
check for creep in hours of idle or next day, 5b increase is normal. if reg gauge equalized with bottle pressure or 10b + diff the rod piston sealing surface need a light resurfacing on a lathe---but 1st you need to replace the closest 1X2mm oring to the piston on the adjustable screw, if that is leaking it will pressurized the reg chamber also.
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I swapped all 5 orings and wiped down the piston a little better. It wasn't a dent after all. Running a thumbnail over it didn't catch on anything. It has been holding air for over 24 hours now. The oring inside the gun (I think 39) was toast. No more leaks so far. I reset the reg as instructed in AoA's video and put my scope back on with very little poi shift if any. I'll paper shoot it in a day or two. Extremely pleased with the results of the fix. Thanks for the advice.
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That's great to hear that it wasn't a dent. Looks like you're good to go! What was it? It sure looked like a dent. Is the face of the reg piston smooth? I'd recommend Chronying it. A damaged reg piston will destroy your SD.
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Before the oring went out I was getting 830fps with a 25 grain pill on power 3 (gun likes it the best). I think the sd was 7 or 8. The streamline I had was more like 3-4
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Yeah, I was never very happy with the SD of my Impact .30. I was getting 5.12 with the JSB 50s when it was new. Then I had the regulator rebuilt. After the rebuild, the SD jumped to 8.33! I was getting an SD of 2.12 with my Daystate Pulsar .25 shooting Hunter Extremes 28.4 gr. The RAW HMx .357 (130 fpe regulated) that I am expecting this month has an advertised SD of 3.00 with the JSB 81s. We'll see.
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Have you sorted your pellets ?
From a bin to another, pellets can be different and not make it possible to accomplished a valuable SD.
I had the same experience with my .30 Impact .
Now I sorted my pellets to make sure I have an accurate reading.
Not to mention the the chrony we use are very sensitive to light changing, pressure etc. They are not accurate.
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No, GQ; I have not been sorting my pellets per se, except to the extent that if I notice a pellet that has an obvious bent skirt or something like that. But, I think that I'm going to start doing that. I bought a digital scale to that end. With my new RAW HMx .357 (130 fpe regulated), I believe it will be worth doing. It will be purely a hunting rifle, so I will be using relatively few pellets compared to my FX Impact that I used for a fair amount of plinkin'.
Your point about Chronys (and other implements of destruction, like digital scales) being prone to calibration and detection issues is well-taken. But, at least I can get a benchmark and monitor consistency. Can you recommend a good pellet-sorter?
Your point about Chronys (and other implements of destruction, like digital scales) being prone to calibration and detection issues is well-taken. But, at least I can get a benchmark and monitor consistency. Can you recommend a good pellet-sorter?
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I just use a good digital scale Marcello it is enough.
Make sure you always chrony at the same ranging place and temperature outdoor.
If you do it inside you make sure the lighting is the same and the exact distance from the chrony.
And for me, the only relyable result is the tight grouping on target.
The rest is not important.
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GQ, OK cool. I bought a relatively good digital scale (0.001 g / 0.015 gr). I have been doing my Chrony work indoors, and I should be able to continue doing that. (I have a .22 rimfire bullet trap filled with rubber mulch.)
I must do my zeroing and ranging outdoors however. I live in a small one-bedroom apartment. I have been using a Primos Trigger Stick shooting tripod. I bought a two-point rifle rest adapter for it, so hopefully that will make my shots more stable. I live in SoCal and it's not exactly a shooting culture down here on the border. I have been unable to find a suitable shooting range that has 100 yard and intermediate ranges. The best I found was a 25 yd range an hour drive away, and it didn't even have sit-down benches that would accommodate a rifle rest! I grew up in rural Pennsylvania where there was a gun shop / range on every block (almost)! The weather and beaches are great down here, but I really miss being able to simply step outside my backdoor and start blastin'!
A little further advice (thanks for this, BTW
: When you weigh your pellets, do you pick a certain weight range of pellets to shoot?
I must do my zeroing and ranging outdoors however. I live in a small one-bedroom apartment. I have been using a Primos Trigger Stick shooting tripod. I bought a two-point rifle rest adapter for it, so hopefully that will make my shots more stable. I live in SoCal and it's not exactly a shooting culture down here on the border. I have been unable to find a suitable shooting range that has 100 yard and intermediate ranges. The best I found was a 25 yd range an hour drive away, and it didn't even have sit-down benches that would accommodate a rifle rest! I grew up in rural Pennsylvania where there was a gun shop / range on every block (almost)! The weather and beaches are great down here, but I really miss being able to simply step outside my backdoor and start blastin'!
A little further advice (thanks for this, BTW
: When you weigh your pellets, do you pick a certain weight range of pellets to shoot?Upvote 0
Mostly you want to be within .010 for your pellets. I'm crazy and go down to .005. Also, you can shoot all the pellets. Just re-zero for your new weight range and all those in that range should be on target.
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Is that in grains? If so, you have a really nice scale! I was not willing to make the quantum leap in cost from the 0.001 g / 0.015 gr model to the 0.0001 g / 0.0015 gr one.
Have you ever sorted the JSB 81s? If so, how many per tin do you get in that range?
Have you ever sorted the JSB 81s? If so, how many per tin do you get in that range?
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