hi i have not long purchased an fx m4 and a scuba tank to fill said fx , my question is this the scuba tank is a 232 bar size [ 3300 psi] and instead of the 250 bar charge into the bottle it is only filling to 180 bar , not sure if i'm doing some thing wrong or not , some advise would be much appreciated, thanks clemmo.
fx m4
- Thread starter clemmo
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If you're using a scuba tank where the max pressure is only 232bar (and you've in fact been able to fill it to that max pressure), you're only going to get that pressure on the very first fill and it will quickly drop after that first fill. More likely, your scuba take at max fill is about 215-220bar at best after it cools down from being filled. From there, after a couple of fills you're only going to get about the 180bar fill that you're seeing...and then it'll continue to go down further each time you fill the M4 until you refill scuba tank again.
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SCUBA tanks are not practical for refilling most modern airguns. The limit that you are experiencing is due to the equalization pressure of the SCUBA tank and bottle being below the desired fill pressure. If your SCUBA tank starts at 232 bar, the maximum pressure that you could possibly reach on your rifle would be ~215 bar for the first fill (this is a rough guess for conceptual purposes, there are calculators that you can use to get an accurate pressure change per fill). The exact equalization pressure will depend upon what pressure your rifle is starting at and the volume of the bottle/cylinder. The subsequent refill will start from a lower pressure (215 bar as per this example).
Since many guns have fill pressures of 230-250 bar, a 230 bar SCUBA tank will only provide so many partial refills. This is especially true on rifles with large bottles, like the impact. A 300 bar SCBA tank would be more practical, if you need air and don't have access to a compressor. A personal compressor (like a GX CS3 or JTS comp1) would be more practical, as you can skip the SCUBA tank all together and always get a full fill.
Since many guns have fill pressures of 230-250 bar, a 230 bar SCUBA tank will only provide so many partial refills. This is especially true on rifles with large bottles, like the impact. A 300 bar SCBA tank would be more practical, if you need air and don't have access to a compressor. A personal compressor (like a GX CS3 or JTS comp1) would be more practical, as you can skip the SCUBA tank all together and always get a full fill.
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You need a SCBA tank they are rated to 300 bar. If you have a tank with 300 bar in it you can carefully fill the gun to 250 bar several times.
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If possible the best scenario you can do with your tank is get a long enough hose so you can set the tank down, hook it to your impact , turn the air on and leave it hooked up and on while you shoot. This will limit you to bench shooting but you will get a bunch of shots off that tank and make it more practical.
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One gauge show pressure in tank , another after regulator , be sure you checking right one when you fill it.
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