FX Impact Question

Is it normal to hear the plenum refilling with air after taking a shot? I can hear compressed air flowing back into the plenum, lasting a few seconds then goes away as the reg closes up.

I have a Gen 1 Impact X, .22 cal with the standard 20mm valve tube (not power plenum). Shooting 18.13 grain JSB’s at 880 fps, with RP set at 105 bars.

Interesting -- for comparison my completely stock straight from the factory Impact Mk2 .22 cal with the power plenum is shooting the same 18.13 pellets, also 875-885 fps with regulator pressure set between 85-90 bar.

I wonder if its the power plenum, or if its difference in the regulator accuracy, or other variables. I'm using a 600mm barrel.


 
Is it normal to hear the plenum refilling with air after taking a shot? I can hear compressed air flowing back into the plenum, lasting a few seconds then goes away as the reg closes up.

I have a Gen 1 Impact X, .22 cal with the standard 20mm valve tube (not power plenum). Shooting 18.13 grain JSB’s at 880 fps, with RP set at 105 bars.

Interesting -- for comparison my completely stock straight from the factory Impact Mk2 .22 cal with the power plenum is shooting the same 18.13 pellets, also 875-885 fps with regulator pressure set between 85-90 bar.

I wonder if its the power plenum, or if its difference in the regulator accuracy, or other variables. I'm using a 600mm barrel.


It’s from your Power Plenum, caused to the PP u have more volume of air that pushes the pellet out, cause of that u need less reg pressure. 👍🏻
 
Is it normal to hear the plenum refilling with air after taking a shot? I can hear compressed air flowing back into the plenum, lasting a few seconds then goes away as the reg closes up.

I have a Gen 1 Impact X, .22 cal with the standard 20mm valve tube (not power plenum). Shooting 18.13 grain JSB’s at 880 fps, with RP set at 105 bars.

If you had the larger power plenum, I would agree with " Its normal" but you stated you have the small 20cc plenum. Its not normal. But is it bad, No. It looks like your gun has a good tune. 105 bar, 880 fps, 18gr pellets with the smal plenum is a great tune. Should you worry? Not today. If your finding your gun to shoot great, dont mess with it. If you want to correct the problem you'll need to clean and deburr your regulator. There's a small hole in your regulator in the black delrin part #c34 you may need to clean out. 

Mont
 
Thanks for all the responses. It’s possible my reg needs a little TLC. I have the AMP reg installed now but will throw jn my HUMA to see if that makes any difference. My valve housing has been ported so that does allow for a little more volume. I also have the larger valve seat which along with the ported housing may provide more fps over a bone stock setup. I also have the new MKII gauges that are hopefully a bit more accurate than the old ones but RP is still relative to gauge tolerance. The refill sound doesn’t bother me just was curious if it was normal or not since I bought my gun used from another AGN member.
 
The more air you use in each shot (big caliber/high power), the faster the reg will fill, as it opens up more. And you will probably hear it. I have an impact with power plenum, and when it is tuned for .177, I may hear low hiss almost unnoticeable. Sounds like a slow leak, and it may last several seconds . I am guessing the .177 use so litle air each shot, that the pressure hardly drops in the plenum. So the reg barely opens, and fills more slowly. The gun shoot just fine, so it doeas not matter. If you have the original plenum, the pressure will drop more, and fill faster.
 
to the person looking for a fx impact i have one that i will sell to you. the gun is the latest model gen5 and in new condition .it has a hawke 30 4 by16 by 50 scope and fx rings .it also has a custom wood stock super nice. i am going to let my new nomad2 compressor go with it it is only a few months old. as is the gun itself. i am getting 935 fps on only 80 bar showing how well it is tuned. by the way it is a .22 cal. w/ 700 barrel . so if intrested contact me at [email protected]. the price is 2000 dollars firm. 
 
to the person looking for a fx impact i have one that i will sell to you. the gun is the latest model gen5 and in new condition .it has a hawke 30 4 by16 by 50 scope and fx rings .it also has a custom wood stock super nice. i am going to let my new nomad2 compressor go with it it is only a few months old. as is the gun itself. i am getting 935 fps on only 80 bar showing how well it is tuned. by the way it is a .22 cal. w/ 700 barrel . so if intrested contact me at [email protected]. the price is 2000 dollars firm.

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Could you post photos please? I would love to see your custom wood stock.