Weird discovery.
I got my first PCP, a Talon SS, just about a year ago. Along with that gun came a standard Air Force scuba fill adapter. Been using it ever since, even after modifying it for use with a nitrogen tank. Cobbled together a filler whip when I got a B50, then modified stuff again to work with my “new” AA S400E. Which is where it gets weird.
When I got the 400, I read through the manual, said fill to 200 bar max. No problem, that’s about 2900 psi, not that much difference from my Talons. One of the cool things about the Air Arms S4XX series rifles is the fill level gauge on the rifle. This gauge can only be used to keep track of how much air you have left, it responds too slowly for filling. But it’s a nice feature. Oddly enough, when I filled it to 200 bar according to my filler gauge, the rifle gauge only showed 150 bar. So which one do I believe? Being conservative with these things, I decided to assume the filler gauge was the correct one.
I have a second gauge on my filler setup, it lets me keep track of how much pressure is left in my nitrogen tank. It’s a glycerin filled gauge, and has leaked both air and glycerin since I installed it. I finally got a replacement for it today, but other than the leaks, it still seemed to work fine. Since there was a question mark about my old Air Force gauge, I went ahead and swapped them out, and then refilled the S400. This time, 200 bar on the filler gauge showed up as 200 bar on the rifle gauge.
So it looks like all this time I thought I was filling my Talons to 3K psi, I was only filling to 2300 psi. No wonder I never had a problem with valve lock! What’s really amazing is the performance I’ve gotten at rather low fill levels. Or maybe my chrony has been lying to me all this time too…
Dave
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Viewing 11 replies - 1 through 11 (of 11 total)
Using a scuba is a good way to calibrate your gauge on the fill station. When the fill to 3000psi at the shop you can then compare that against your gauge. Just make sure you dont take a hot tank from the scuba shop. You need them to check the pressure after filling on a stone cold tank.
Well, I only fill to 1900 psi and I get the same performance other guys on here claim. I broke my gauge yesterday so I’ll be having to recalibrate my setup when my new gauge gets here. It will be interesting to see if they both read the same….
I really like filling to only 1900 psi because I get WAY more fills off the scuba tank before its “useless” and needs to be refilled.
I wouldn’t trust a brand new gauge without checking it against a known reference… but once I see where my gun gauge is compared to a fill gauge – I’ll believe it.
But like Dave said – No one fills using them – Or they shouldn’t because they react too slowly. Using them to check that a gun is filled or needs a fill isn’t a huge deal if it suddenly decides to read differently.
I understand.
But having dealt with dozens of those little gauges over the years what I do know is they are about the cheapest one you can buy about $5-10. It may last it may not.
Trust it if you wish.
Adam…. I dont think you caught the boat yet….His 400 gauge IS accurate…..
The little gauges are not known to be very reliable that they include with the guns. I have one also and it is not accurate on my 410. Get a better gauge for the fill station and that will give you the best reading.
The little gun gauge AA can vary quite a bit. Even a watch that cant keep time is right sometimes.
Score 2 points for YN, Adam, the ADD meds aren’t working, pal :-). Yeah, YN nailed it, the rifle gauge seems to be the accurate one here. Maybe there was a clue with the old AF gauge, it never did zero out. Even with no pressure, it always showed about 20 bar. So now I have to figure out what my Blodnob valve wants for fill pressure, I thought it was 2600, I guess the real number is 2000? Later.
Dave
I never trust the gauge on the gun. Have not a clue as to why the rifle gauge change…LOL. Probably just to drive you crazy. 😛
The gauge on the gun was accurate all along… His 400 showed 150 bar on gun when old fill adapter gauge showed 200, once he replaced the fill adapter gauge, both showed 200…
Strange indeed.
I never trust the gauge on the gun. Have not a clue as to why the rifle gauge change…LOL. Probably just to drive you crazy. 😛
Very interesting. Let us know how your gun performs at a true 3K fill.
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Along the lines of what Adam is saying, if I took my A.F. scuba adaptor and charged my gun tank off a scuba tank they had sitting there (read 3K cold) and my tank stopped filling at 3K is that a reliable way to verify my gage is accurate? If the short answer is no, where does one go to get a gage checked and calibrated?