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Layman’s terms for fills

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Chopper61

Chopper61

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Oct 26, 2020
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Florida
Ok I got a 300 cc reservoir on the gun. A great compressor but because I’m down here in Florida I don’t like to work it with the high heat and humidity. I got top of the line filtration with check valve that opens to fill at 2000 psi I just want to know without the math how many fills could I get with a 6.8-9 liter tank or 60 minute sorry for being dumb on this in asking my philosophy is fill the bottle at night when it’s cooler then fill the gun with bottle I know about the calculation on certain sites but it always comes up to 0 fills! I may be doing something wrong but not sure I have several guns I’ve been doing this for a while several caliber is the gun in question is the 357 9 mm with a 300 cc tank reservoir any feedback would be greatly appreciated I just don’t wanna spend money for nothing thank you very much
 
Pyramyd Air and Airguns of Arizona (and probably others) have calculators for this but your post does not include all the required data and some of it is not in the required format. They want the tank volume in cubic feet, for instance. You also need to specify how high in pressure you want to fill your gun and how low you will let it go before refilling. To give some idea, I used a 66ft3 tank (about the size of my 45 minute SCBA), 4000 psi on the tank, 3500 psi gun fills and refills at 2000 psi. With a 300cc gun bottle, Pyramyd's calculator says 8 fills. The other thing to keep in mind is you don't have to quit shooting when your tank falls below 3500. If your regulator is at 2000 you would still have many usefull shots with a 3000 gun fill.

What will give you a "zero" answer is trying to fill a gun to the same pressure as the tank. If the SCBA is filled to 300 bar it can't really fill a gun to 300 bar even once. It would be close the first time but will be lower each successive fill. That is not terrible unless you are filling a big bore or something and it's unregulated and your velocity will be different if you do not fill to 300 bar. For little guns like I shoot, the regulator is closer to 2000 psi or less and all but one of my guns are limited to no more than 250 bar fills (about 3500 psi).

I don't see a reason to worry about humidity in the air when you are using your compressor, however. Water is always going to come out during the compression. A little more will come out when the ambient humidity is higher but it's humid here in South Carolina in the summer too. My SCBA tank still gets dry air and I know it did because I use color changing dessicant as my second filter on the compressors output. When the dessicant is at least partially still the original orange color I know it did it's job and the air in the tank is dry. Even in the summer it takes several tank fills for the dessicant to change color on my setup.
 
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JimD said:
Pyramyd Air and Airguns of Arizona (and probably others) have calculators for this but your post does not include all the required data and some of it is not in the required format. They want the tank volume in cubic feet, for instance. You also need to specify how high in pressure you want to fill your gun and how low you will let it go before refilling. To give some idea, I used a 66ft3 tank (about the size of my 45 minute SCBA), 4000 psi on the tank, 3500 psi gun fills and refills at 2000 psi. With a 300cc gun bottle, Pyramyd's calculator says 8 fills. The other thing to keep in mind is you don't have to quit shooting when your tank falls below 3500. If your regulator is at 2000 you would still have many usefull shots with a 3000 gun fill.

What will give you a "zero" answer is trying to fill a gun to the same pressure as the tank. If the SCBA is filled to 300 bar it can't really fill a gun to 300 bar even once. It would be close the first time but will be lower each successive fill. That is not terrible unless you are filling a big bore or something and it's unregulated and your velocity will be different if you do not fill to 300 bar. For little guns like I shoot, the regulator is closer to 2000 psi or less and all but one of my guns are limited to no more than 250 bar fills (about 3500 psi).

I don't see a reason to worry about humidity in the air when you are using your compressor, however. Water is always going to come out during the compression. A little more will come out when the ambient humidity is higher but it's humid here in South Carolina in the summer too. My SCBA tank still gets dry air and I know it did because I use color changing dessicant as my second filter on the compressors output. When the dessicant is at least partially still the original orange color I know it did it's job and the air in the tank is dry. Even in the summer it takes several tank fills for the dessicant to change color on my setup.
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I appreciate your information very much. I must be doing something wrong in the calculator as I put on another post yesterday. It is a lot easier to go from tank to rifle. My 3 liter gives my 250cc and my 200 cc 11-13 in regards to the cc’s I want to go out which is not in my backyard because it’s an rv park. I do have several places which are safe to shoot. I want to take a tank with me. Again I just don’t know what size tank to go through 8-11 mags
 
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Thanks bro, I’ve been into air guns for a while I have several.25’s this is my first big bore. My Yon hang compressor still works but bleeding out corrosion formed on the fittings it’s all from the humidity down here. I’m not complaining I got close to 3 years out of it. So I got back into it I think it’s amazing how much the sport has progressed in every area in the last 3 years! So maybe I’m paranoid with compressor’s and stuff. What I had until that happened was cool I was even surprised by the new compressor I picked up, 3 years ago you couldn’t come close under$1500! Pellet vendors and everything. So that’s my situation and I appreciate your input and time. I still can’t figure out what I’m doing wrong with the calculator. I’m hoping I can put something together where I can get 4-5 fills
 
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Is it the AEA 357 Max which fills to 4500 psi you are trying to fill 4-5 times? If so, the high fill pressure makes a bottle a bad match for this gun. Most bottles are only rated for 300 bar which is not quite 4500 so you cannot fully fill the gun even one time with a bottle filled to 300 bar. But it looks like filled to 4500 you only get 12 shots. I would assume a lower pressure fill would give you some shots but not 12. If you are willing to accept less shots per fill a bottle might work. It could probably give you 50 shots but you might be filling every 5 shots or something like that by the time you finish.

A small compressor may be a better match for this gun. Something like a GX CS2 powered by a battery or your vehicle. It would probably take something like 5 minutes to refill the gun but would give you at least 300 bar each time. I think it only weighs about 15 lbs so it's pretty portable. Target Forge has several videos out on this compressor including one where he adapts it to use 18V DeWalt power tool batteries he already had.
 
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JimD said:
Is it the AEA 357 Max which fills to 4500 psi you are trying to fill 4-5 times? If so, the high fill pressure makes a bottle a bad match for this gun. Most bottles are only rated for 300 bar which is not quite 4500 so you cannot fully fill the gun even one time with a bottle filled to 300 bar. But it looks like filled to 4500 you only get 12 shots. I would assume a lower pressure fill would give you some shots but not 12. If you are willing to accept less shots per fill a bottle might work. It could probably give you 50 shots but you might be filling every 5 shots or something like that by the time you finish.

A small compressor may be a better match for this gun. Something like a GX CS2 powered by a battery or your vehicle. It would probably take something like 5 minutes to refill the gun but would give you at least 300 bar each time. I think it only weighs about 15 lbs so it's pretty portable. Target Forge has several videos out on this compressor including one where he adapts it to use 18V DeWalt power tool batteries he already had.
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Yes it is. I’m annal so I want to understand every acceptance. I mentioned earlier the humidity where I’m at here is insane! I have a new GC c4 pump with a filter and check valve which released at 2000 psi. I know it works great on filtration because I just changed the elements that I had in there for a year on a ton Heng which does work but issues. The filter could have still been used, however I do have a Benjamin that’s rated that I could use off my golf cart in the right sequence of battery placement. I’m worried about the damn water. I don’t even shoot down here in the summertime because it’s so damn hot out it’s not enjoyable anyway no matter what time of day so this is an end of September until roughly the end of May type of sport for me
 
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Yes, I believe that is called tethering and it seems to be common with a big bore. I've never done it but it might help you because the pressure in the gun will fall more slowly. It would limit your mobility but if you want to shoot from a fixed position it seems like a good option.

I don't think the CS4 is set up for use off a power tool lithium ion battery but I believe the motor is 350W which is a little bigger than the 250W of the CS2 but still seems like it could work and avoid the need to have a vehicle handy. But the batteries are not cheap if you don't already have them. I have a few Milwaukee batteries I could use so if I get one of these little compressors I will want to set it up this way. Target Forge has a video about changing a CS2 to use his DeWalt batteries.
 
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