As you are an engineer and a scientist of these things. I ask you to try something, if you are inclined. Try Nitrogen. I have heard it's way more stable than air. I haven't researched it, or even tried to locate a fill source. Especially one that can give 4,350psi. But I wonder if it would make a difference. 🎯
I ENJOY YOUR AVENGER SERIES...JUST BUYING MY FIRST PCP. You keep mentioning "temperature"... I worked in a military calibration laboratory (to work to national calibration standards; our lab had tobe 66 degrees +_ 1; at some(?)specified Relative humidity, and that was just the electronics lab area.I believe the physical dimensional lab was tighter .) : Here's something to think about: A huge factor "Air temperature" affects is the "relative humidity" (RH):Warmer air holds more water vapor(making it denser). So In my thinking; if you fill from a compressor when the outside RH is one value; the refill in mid afternoon when the rh is different. the outside (compressed) "Air" will have different qualities. Eventually the different air "values" in the rifle reservoir will mix and average out. Cheers!
The wood stock also interferes with the barrel / air chamber stack. This can be seen taking the rifle apart and then putting it back together in hot weather. The plenum and trigger area won't fit into the stock! One must sand the stock down to allow the barrel assembly to free-float. This may also fix the PO shifting.
I don't know about the reg and plenum on the Avenger, but I can speak on my Origin. I don't like to store it empty, so I've been putting it away with 1500 or 2000 psi. Then I take it outside to acclimate (gun parts, not the air) for about 30 min before shooting and bleed all the air out. Then I fill it with the compressor and shoot away. I've gotten way more consistency shot to shot and fill to fill this way. If I shoot "old air" I get variance in my groups. I still get differences in my scope zero from day to day, but I think that has to do with air density. It's just just a fact of pcp rifles that they don't seem to stay zeroed perfectly from day to day. It is what it is and just something I've learned to live with. One other thing is after I fill from the compressor, I let the gun set about 15 minutes. I feel the air going in is somewhat hot. Bottom line, it's all just quirks of owning and operating a PCP. I don't have the same issues with my springers or multi pumpers. Good video and info.
Thanks yea that maybe because of the EPT keeps pressure on the air in the cylinder after airing up...resulting higher temperature staying consistent in the cylinder and when air cools in the gun from sitting the EPT moves or shift up/down the cylinder
Sorry James, you spent a lot time on this subject, but it's not based in science. I'm a physicist and I'm not buying the two different air types argument/theory. The air being compressed is the same whether it comes thru a hand pump, a compressor, or even from previously stored air in a larger bottle, it's the same atmosphere being compressed. Sure the temps and moisture content will vary depending on the speed it is being compressed, but moisture is filtered out and air temperatures will equalize and stabilize with any air still inside the air chamber within a very short period of time. There will be no atmospheric inversion layer forming inside a vessel, air will thoroughly and quickly mix, and will soon become the same temp, and within time become the same temp as the ambient air outside the vessel/air chamber. The bottom line is the total air pressure inside, the potential energy stored in the chamber or regulated plenum, not where it came from or when it was placed there. The air pressure is all that matters at the transfer port the moment you pull the trigger. I would suggest you explore the effects of different air temperatures on the barrel of you gun when you see POI shift at different times of the day.
I suspect its a physical problem in the regulator, because I fill only with a hand pump and indoors in climate control and have this creep problem and it also sometimes happens after a day or less of being charged above set pressure but not immediately used (hand pump only so I fill to max, shoot usually at least 30-40 shots and then shelf for next time). I have to wonder if perhaps the mechanism is maybe pushed up more under filling or temp based increases, and takes the shocks of vibration and pressure changing internally from firing to work its way back down. Sorry, I cant remember the correct term for the nylon or whatever plastic stuff in the regulator right now... When I muster the Cares to do it, I may try lubricating that plastic inside the regulator. I seem to recall its also very soft and easily damaged by basically any force or movement past the intended end of the screw on the regulator adjustment putting divots in it.
Exactly... but a bottle is filled, with different air each time! So each time you fill your bottle, bleed off the previous fill. Then air the bottle up. De-gas your gun, and fill from your bottle. Reset reg by firing your gun. So when you re-fill your bottle, de-gas your gun! Thehen refill, dry fire it agin to rest the reg pressure if needed. By using the Bottle fill method you are using the same air density until it is time to refill your bottle agin. Then you start the process all over agin!
I’m about to test this process with my Umarex Origin but it’s not a regulated gun. Would it still be necessary to dry fire the 5 shots or is that only for regulated air guns?
@@mattc6395 only to set the reg on reg'd gun. But let us know about how the air density affects ur fps/fpe 👍🏻 From each fill for each day. Completely 0 psi for each day filled👍🏻👍🏻👍🏻
@@ezrabrook3993 Thanks! Also I assume I need to fill the gun up using air from outside instead of filling it up inside where there’s a different temperature? And I hear people saying leave it outside for 30 minutes, then fill it up, then wait 15 minutes for that air to cool. Couldn’t I just take the rifle outside and fill it as soon as I take it out then let it adapt? I apologize if this is a stupid question it’s just a lot of this is going way over my head. Im new to pcp shooting and all I have it my hand pump. No way of testing fps/fpe unfortunately:/
Hey James, I was smiling all along. As you were explaining how the different air affects POI, I'm thinking that my little Stormrider with a reg doesn't have much if any POI even out to 45 yards! :), and that reason is exactly what you were explaining, I use my hand pump only, never the compressor or the bottle. Another Great Vid.
I know this is an old post but newbees are still viewing it. Surely someone on here took high school chemistry. Gay-lussacs’ law states clearly that the pressure of any gas is directly proportional to its temperature. Charles’ law states that the pressure of any gass is directly proportional to its volume. If you lower the pressure (allow it to pass through a regulator) The temperature will decrease. If you increase the pressure (pump the cylinder with more gass the Temperature will increase. If you transfer gas from a cylinder to another cylinder (your air tube) the gas will cool when it decompresses and then warm as the pressure rises as the air tube pressure increases. All gasses are in constant motion and will quickly mix in an enclosed space unless at absolute zero temperature.
Thanks for another good video. I was having the same thing going on. I have since bought and tested a power plenum it seems to help a little but not enough to justify.
Another thing I noticed is to clear up the flyers I’ll just do a mag dump and as I’m firing away the grouping starts to come together . And that’s after I refill it with the tank
All this stuff just makes me wish they made the Diana stormrider in .25 cal. It don't have these problem and puts pellet on pellet all the time. I can't even sight my wood stock avenger in. I max the elevation on my scope out and it still shoots 5" low
Mine only has the horizotal poi shift and is caused by the air tube not fitting tight in the barrelbands. Just check al your barrelbands for slack and fill it with something like a toothpick or something similar. I also 3d printed an extra barrelband and got rid of the poi shifts.
Air being different from tank, compressor, or pump doesn't make sense. Case in point. Set the rifle down and let it cool before shooting. If set down long enough the temperature will normalize and the temperature will be uniform.
Hey James I thinking if I hook up a 3L carbon tank direct on the gun and open up the valve. The tank and gun tube at the same pressure both fill the day before. Not fill at 4300 psi mabye at 3500psi less pressure to the regulator. I think like the Gauntlet first gen. We did have that problem back then. So my test will be: Ava .22 whit the bigger plenum upgrade. 3500psi tank and tube. Reg pressure at 1400psi 2 turns on HS Shooting the cross man premiere 14gr at 50yards. I let you known how it goes
James, appreciate the testing. Hot air in a small plenum made of a large mass of metal will cool quickly as the metal absorbs the energy. The heat conductivity of the metal determines the rate of energy absorption. But a thin walled air tank of much less metal will cool quickly due to the larger surface area that dissipates the energy much more quickly. I think you are showing that equilibrium temperature is required before a consistent pressure and mass of air is transferred by the plenum, regs, and tank to the pellet or slug. What about your idea of the dual reg interaction? Where you were proposing that the 2nd reg pressure shouldn’t be less than half the tank reg pressure to avoid a poi shift? And both ideas you’ve proposed still require that the barrel and shroud are stabilized, correct?
Here is an explanation from the FX world that goes over tank and plenum temperature and pressure. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-LGNGO500WFM.html
Hey just watched that video about halfway when he started talking about his reg setups on the impact...I did what he mentions exactly in the prior video to this one about letting the reg/temp settle now on to the Avenger ...the 22cal has 15cc plenum that is sealed and is encapsulated in the manifold now the take away is most people use the oiless/waterless air compressors which is part of the problem too , I'll post a video about this soon cause Air Venturi even confirmed my findings....if there's air in the gun already then refilling it to a certain pressure causes the air to warm up inside the gun and it gets warmer in the plenum first as you see the gauge increase from the gun prior to re filling...hotter air is toward the plenum end, colder at the fill nipple...when you let it sit the colder air pressure overpowers the hot air in the plenum keeping it warm as shown on the gauge...if cold air was in the plenum the gauge shouldn't creep up it would creep down, which never happens unless gun is literally frozen
@@ALLABOUTAIRGUNS yeah, this is standard physical chemistry of a gas in an enclosed space. Compressing air raises the temperature of the gas. Nitrogen, helium, argon, and the mixture known as air all increase their temperature due to the compression process. Filling from a tank is probably less extreme than from a small non-oil lubricated compressor like I use. My Avenger air tube is warm to the hand after filling. The plenum and tube likely cool at different rates. Dry firing probably helps with mixing the gas in the separate chambers. If you dry fire a couple of times, hike for an hour, then take a shot at prey, then I bet the pressure is pretty equal for a follow up shot. But, not dry firing, and immediately shooting at targets would probably have a very noticeable difference in pressure over a period until temps and pressures are in equilibrium. I’m a chemist by trade so “work” in a closed system by a gas took me back to physical chemistry in college. 😂 Like if you passed P-Chem! 👍🏻😂😂😂
@@dow4hurst lol I am an engineer by trade haha so I know what you mean...always going back and double checking gas laws and research things that I forgot since highschool/college chemistry courses
James, nothing to do with this video. Do have another issue. Not a complaint, just different. I have an origin, I use the origin hand pump. I can go from empty to full in 35 pumps. I only get 20 shots. Hammer spring is turned down to shoot 750 fps. Why so few pumps, "not a complaint" why so few shots? "Tiny complaint" thanks.
@Mykahel Combess I have suddenly developed the same problem. It seems most likely it is he rifle's gauge, telling me I am full way before I actually am. And once I get to empty, I am still showing about 1100 PSI. Until this problem suddenly developed once I returned from 2 weeks vacation, I would, starting at 3600 PSI, after 45 shots, suddenly drop from 1900 PSI to out of air though showing 400-600 PSI on the gauge. (I think that, once out of air, I should have had only maybe 100 PSI showing on the gauge. Then it was 400-600 when I 1st noticed it, and now 1100. Also, when you go to full after 35 pumps(rather than 120+), what pressure shows on the pump gauge? They should be pretty darn close. My pump and compressor show at least 600 lower than the rifle's gauge. What PSI are you showing when out of air? We may have the same problem, I am just beginning to investigate. I am going to de-gas and see how much PSI I have(should be about zero). I am also going to call Umarex. Let us know here if you figure anything out about what is causing your problem, I will try and do the same.
I’ve noticed after refilling with tank or pumps I get insane flyers then after 10-12 shots they start to group again. Sig virtus pcp 22 crosman premier domed
I know... the air in my auto tires goes up and down alot with temp. changes. It gets cold ... my tire pressure lights can come on to indicate low tires. These guns are doing the same thing.
Sad to,say,,,,,i only use a hand pump to fill my air rifle and its a bitch ,,,,but i have reg creep now that it rises up 1 ,,,to ,,2 marks higher ,,,,so with that said ,,,whats the cause ,,,,im not switching between hand pump and compressor due to not owning one,,,,but i am in the future ? Solve my,problem
No, if gun is empty... hot air starts in the plenum and smaller space gets hotter faster...then the temperature varies all the way through the air cylinder to the fill nipple...if the gun is ambient temp with air in it , the plenum (reg psi) will show higher than what you set it cause the air is warmer...warmer air =higher psi so you have to dry fire to reset reg pressure (temperature)
So in the colder days when i degas my gun then fill it back up i need to let it cool before i shoot because when i shoot the air is cooling faster so when i fill again there will be 2 different temps of air in the system. Right or no?
You can degas only if you want but if gun is left outside to become that temp and you add more air , just dry fire it about 5x , to reset the reg and air flow will cool it off
Thanks james for your ansewer but what i am asking is when i fillvon a cold day and shoot does the air cool fast enough that i need to degas before i fill again or will the the next fill be ok to just keep shooting
I live in central texas so it only gets real cold sometimes but it does get pretty cool on alot of days this time of year just not as cold as it does where you live lol
So there is no one for me to ask or talk to in my area so i have a hard time figuring out things on why my gun is doing so i just thank you for your help
Hello , great imformative video , i have the same issue with my fx impact M3 .22 , but my poi shifts about 2 cm to the right and after some shooting or time it shift back to its zero, i looked over the barrel , scope , changed ammo nothing helped , still the reg but i thought if i had regulator creep it wont shift in that consistent way it is doing, i would appreciate if you have any idea or faced something like that , left to right shift and back again. And thanks in advance.
I am currently working on this issue...my guns are doing the same but its only happening or noticeable due to our weather changing here...about 30 degrees in the mornings and 70 degrees during the day
Hey James. Have a question for you. My Maverick Sniper 25 cal shoots like a dream but very temperamental in its POI. It would shift POI, specifically the windage, not so much on the elevation. It happens almost every week yet still shoots sub-MOA groups at 50 and 100 yards all day all the time. I had installed the carbon fiber sleeve as well as a barrel band but still, it will change the POI, sometimes as big as 1.0 mil at 50 yards and its very frustrating. It will be dead-on one day, then will change POI the next. My air source is always from the SCBA tank. My gun is factory tuned at 145 Bar at the front and 110 Bar at the back. What's your take on this issue? Any input would be appreciated.
@@gmdandee I'd switch to lighter pellets or turn the power down by hammerspring adjustment, that's usually an indication of veering from a right hand twist rifling...with that heavy of a pellet 25.4gr should impact more left ...not sure what 700mm barrel is in the Maverick sniper...either 1:18 or 1:24 twist is what I am seeing on FX website
@@ALLABOUTAIRGUNS Thank you so much for the advice, James. I will surely give it a try. The best accuracy I attain is at maximum hammer spring tension, that's the reason why I set it that way. Other than the random shift of POI, the gun shoots awesome. More power to you and your channel.
This is why I stop shooting Air Venturi. They're defective and way too sensitive. Barrels shift and the regulators are trash. All 3 mine collect dust.I shoot better quality.AVA is Straight trash! Problem solved. Ed snipper💥💪😎
@@BriceP.O.I. yep, 625 for both or 335 for 1! They shoot and work. 2 packages of ammo come with one or 4 packages of ammo Come for both! They both have work done and are new, and have moderator suppressors on them installed! They just carry regulator creep and won't hold zero too long is all.
