Tuning New Artemis p15 dropping fps

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montana1

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Apr 5, 2024
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Hi guys.
Bought a new Artemis p15 .22 2 month ago.
Fps was 850 steady on 30 shots jsb 18.13. From 230 to 130 bar.
Did around 1500 pellets so far.

2 days ago my POI dropped so I checked the chrono and fps was 790/ 800.

The Hammer spring reg is turned clockwise to the maximum from factory ,can't turn further.

I read many post that some guys got 875/900 fps on p15 out of the box.

Any help finding the problem is appreciated.

Thank you
 
All good suggestions, I think. Some may be surprised that increasing the hammer spring force does not always increase velocity. It may decrease it. It is very important to find the hammer spring force that results in maximum velocity for the regulator setting. If you are at maximum, I suggest decreasing hammer spring force in 1/2 turn increments until velocity drops. If it goes up, do not be surprised and keep decreasing force until it goes down. Then go up 1/4 turn and see if it increases or not. The usual recommendation is to set the hammer spring to deliver 5% less than the peak velocity. That improves efficiency. I like to test small increments under the peak to see if it affects accuracy. If 5% under the peak is too slow for you then you would need to increase the regulator setting.

I get 800-825 fpe on a 21 grain H&N Baracuda Match pellet in my P35-22 with it's factory regulator setting any my tweaks to the hammer spring. So your expectation of 850 fps on an 18 grain seems reasonable to me.

It could also be a regulator issue. My P35s have not had problems but it still seems possible. If the regulator is not working, I would expect the maximum velocity to occur close to the former regulator setting and the velocity to be lowest at maximum fill pressure. I've never had a SPA regulator apart but rebuilt a Huma recently. It was simpler than I expected. But I doubt you can get a rebuild kit like Huma offers for theirs. The huma rebuild kit is O-rings, silicone grease and one plastic disc (that seals off the main air supply).
 
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Since this groundhog is really trying my patience, I figured I would reply while I wait. Everyone here is giving solid advice and it can take some testing to figure it out. Hopefully you understand PCP’s. I agree it could be the hammer spring giving up the ghost because it was cranked to the max. Which to get 850fps, it shouldn’t have to be. Your reg could have finally taken a set and it’s nowhere near where the original set point was. Or your reg just plain failed and now you’re in the bypass mode and no P15 can crack the valve with 250b behind it. My suggestion is shoot a bunch of shots out of it and record the speed. See if it eventually starts getting faster. If it seems like you are shooting a ton of shots and it’s taking forever to get to 130b, report back to us the results and we’ll get you fixed up.
 
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Ok guys so I did the test starting from 230 bar till 165 bar.

Velocity started low between 230 bar / 200 bar then started to jump up from 195 bar to 165 bar.

Attached is a photo of the results.

Shall I go to 130 bar or this is enough to find what's wrong please.

Thank you

1714819927280455577162110542229.jpg
 
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Vetmx said:
Since this groundhog is really trying my patience, I figured I would reply while I wait. Everyone here is giving solid advice and it can take some testing to figure it out. Hopefully you understand PCP’s. I agree it could be the hammer spring giving up the ghost because it was cranked to the max. Which to get 850fps, it shouldn’t have to be. Your reg could have finally taken a set and it’s nowhere near where the original set point was. Or your reg just plain failed and now you’re in the bypass mode and no P15 can crack the valve with 250b behind it. My suggestion is shoot a bunch of shots out of it and record the speed. See if it eventually starts getting faster. If it seems like you are shooting a ton of shots and it’s taking forever to get to 130b, report back to us the results and we’ll get you fixed up.
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Hello can you please have a look at the test i did per your request. Its posted under your ́reply thank you
 
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I think what you posted is good enough. You have a reg problem. You are actually shooting the gun unregulated. Back when we all were messing with P15’s, most of us just immediately installed a Huma reg. The factory regs in those China guns were a crapshoot and some took a couple pounds of pellets to break in, then they still failed. If you’re not buying a Huma, you’ll need to replace all the orings in the reg. And while you’re at it, do the whole gun. That’s what we did. The factory orings in those guns are sub par.
 
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Vetmx said:
I think what you posted is good enough. You have a reg problem. You are actually shooting the gun unregulated. Back when we all were messing with P15’s, most of us just immediately installed a Huma reg. The factory regs in those China guns were a crapshoot and some took a couple pounds of pellets to break in, then they still failed. If you’re not buying a Huma, you’ll need to replace all the orings in the reg. And while you’re at it, do the whole gun. That’s what we did. The factory orings in those guns are sub par.
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Thank you very much
 
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Vetmx said:
The factory orings in those guns are sub par.
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I am not sure about that. I recently serviced a few Artemis rifles including my own. All are older rifles like mine that is 6 or 7 years old. When I opened it for the first time, It had still all it's original O-rings in it. Since I replaced it with O-rings from a reputable industrial supplier I have to do it more often now.
 
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I’ve had a Huma in my P15 since 2017. It went into the bypass mode two years ago and I had to replace the orings in the Huma. No reg is exempt. But at least with a Huma you can use the markings on it to be at least close to where you think you need to be. Once you get your reg issue sorted, you will have to properly tune the gun. Your maxed out hammer spring tells me your gun was not set right out of the box. It’s not surprising with those guns. But you can turn it into a good gun. Just keep an eye on your linkage and don’t over tighten anything with those buttery screws and threads.
 
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Caliber 22 said:
I am not sure about that. I recently serviced a few Artemis rifles including my own. All are older rifles like mine that is 6 or 7 years old. When I opened it for the first time, It had still all it's original O-rings in it. Since I replaced it with O-rings from a reputable industrial supplier I have to do it more often now.
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That’s because the original orings would actually swell. It was weird. And if you let them sit on the workbench for a day they would shrink back up. Maybe it was planned by SPA, I don’t know.
 
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With these guns I think there should be a certain approach. If you don’t go whole hog on them the second you open the UPS box and blueprint the gun, just shoot it. Then do normal tuning. But the moment something fails, then take that opportunity to tear the gun down not only to learn it but to reassemble it with good orings, lube and fasteners. Then you’ll know what’s in there. I’ve found horrible scratches where orings sit on SPA guns. Some guns internally look just fine. But it’s good to know.
 
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jarmstrong said:
I wish he would have kept shooting till it came off the reg, I think his reg might be to high

as to tuning to the plateau or the knee,,, I tune to the knee or a hair above, it is about first shot velocity, over conserving air for the best mpg result
anyway, that is how I do it
my P15 still has the factory reg,
get that groundhog😁
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That would mean suddenly his reg set point jumped up and that’s why his gun started shooting in the 790 range. Did it jump up or just bypass. When my P15 and Lelya went into the bypass mode, I got an incredible amount of shots starting way below my original velocity. He was already at 50 shots from 230b to 165b. Something suddenly changed. If he has to take the reg out to adjust it back down, why not just install new orings or a new reg. Either way, the gun has to come apart.
 
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