Bobydazzler Posted June 21, 2018 Report Share Posted June 21, 2018 .....another one for all you seasoned veterans! Perhaps being a bit thick here but there's something I don't understand. Topped up a rifle (200cc buddy bottle)....from 90 bar to 200 bar..... from a 7lt 300 bar cylinder approximately 12-15 times now and the cylinder's struggling to reach 200 bar (reading off the cylinder gauge) It's a brand new cylinder and I think the guy in the dive shop said something about getting more in it next time (?) First 8-10 refills were no problem but now it reaches around 180-190 okay then run's out of puff before falling a bit short of 200. I was under the impression from a calculator I found online somewhere that I would achieve upwards of 30-35 refills? Is this normal? What will happen over more, successive refills.....will the cylinder embark on a downward spiral of top up amounts?? Thanks for any help Bob Quote Link to comment Share on other sites More sharing options...
figgy Posted June 21, 2018 Report Share Posted June 21, 2018 You only have so much air down to 200 BAR, so will only get a limited number of refills. This normal. Quote Link to comment Share on other sites More sharing options...
Bobydazzler Posted June 21, 2018 Author Report Share Posted June 21, 2018 Aye, just this minute read a post explaining it....cheers bud! Quote Link to comment Share on other sites More sharing options...
Guest Posted June 21, 2018 Report Share Posted June 21, 2018 Honestly, get a hand pump. Quote Link to comment Share on other sites More sharing options...
Walker570 Posted June 21, 2018 Report Share Posted June 21, 2018 as above I'm out tomorrow and my rifle may run out of puff, so I will just take 3 mins time out and pump it back up ...in fact I will also drink a mug of coffee as well in that time. Quote Link to comment Share on other sites More sharing options...
oldypigeonpopper Posted June 21, 2018 Report Share Posted June 21, 2018 hello, did you check the cylinder guage after filling Quote Link to comment Share on other sites More sharing options...
Bobydazzler Posted June 21, 2018 Author Report Share Posted June 21, 2018 (edited) Many thanks fellas 3 slipped discs and hand pumps don't get along (otherwise YES, love being self sufficient) 2 hours ago, oldypigeonpopper said: hello, did you check the cylinder guage after filling Not sure what you mean oldypigeonpopper, gauge sat at about 190-195 when trying to top it up to 200....some slow turning didn't seem to have any effect so turned off at that. Edited June 21, 2018 by Bobydazzler spelling Quote Link to comment Share on other sites More sharing options...
oldypigeonpopper Posted June 21, 2018 Report Share Posted June 21, 2018 (edited) 10 minutes ago, Bobydazzler said: Many thanks fellas 3 slipped discs and hand pumps don't get along (otherwise YES, love being self sufficient) Not sure what you mean oldypigeonpopper, gauge sat at about 190-195 when trying to top it up to 200....some slow turning didn't seem to have any effect so turned off at that. i was thinking maybe the dive shop did not fill the cylinder enough to get the max fills, quote getting more in next time Edited June 21, 2018 by oldypigeonpopper Quote Link to comment Share on other sites More sharing options...
Bobydazzler Posted June 21, 2018 Author Report Share Posted June 21, 2018 Ah okay thank you Quote Link to comment Share on other sites More sharing options...
silver pigeon69 Posted June 21, 2018 Report Share Posted June 21, 2018 You can work out how many fills etc you will get by converting the air in the cylinder into LFG's. Litres of Free Gas. 7 litre cylinder @ 300 bar: 7 x 300= 2100 LFG So if you rifle needs topping to 200 bar from say 165bar: 35bar x (size of cylinder in rifle (if 2 ltr) 2= 70 LFG your 7 litre cylinder can be used down to 200 bar so you have 100 bar to use. 100 bar X 7ltr= 700 LFG therefore 700/70= 10 You will get 10 fills from your 7 litre if you refill your rifle from 165bar to 200 bar. 2 hours ago, oldypigeonpopper said: i was thinking maybe the dive shop did not fill the cylinder enough to get the max fills, quote getting more in next time If the dive shop fills it to 300 bar, when the cylinder cools it will probably drop to 280-290. We used to fill out 200 bar cylinders to 210-220 and they would settle at around 200 when cool. Quote Link to comment Share on other sites More sharing options...
Bobydazzler Posted June 22, 2018 Author Report Share Posted June 22, 2018 Thanks silver pigeon69.....that's a great formula to copy & paste! We fill from 90 back up to 200 bar, so using your formula that means.... 110*0.2 (200cc size of buddy bottle) = 22 LFG 100*7 = 700 LFG 700/22 = 31.8 fills .......after approximately 12-15 refills the cylinder is definitely struggling to reach 200 bar.....have we been short changed at the dive shop? Quote Link to comment Share on other sites More sharing options...
Bobydazzler Posted June 22, 2018 Author Report Share Posted June 22, 2018 .....or is this the 'wasted air' someone kindly mentioned on another forum? Quote Link to comment Share on other sites More sharing options...
silver pigeon69 Posted June 22, 2018 Report Share Posted June 22, 2018 Are you getting 300 bar when your cylinder is filled by the dive shop? do you wait for it to be filled and if so is it quite warm after filling? Do you have a pressure gauge on the cylinder whip? I presume the dive shop has facilities to fill to 300bar and that you have requested a 300bar fill? Quote Link to comment Share on other sites More sharing options...
oldypigeonpopper Posted June 22, 2018 Report Share Posted June 22, 2018 1 hour ago, Bobydazzler said: .....or is this the 'wasted air' someone kindly mentioned on another forum? hello, you will always loose a bit of air filling a PCP when you open the release valve to take out filling adapter, next time see how much they put in to refill cylinder, i would aim for 30 fills. Quote Link to comment Share on other sites More sharing options...
Bobydazzler Posted June 22, 2018 Author Report Share Posted June 22, 2018 Thanks oldypigeonpopper, I agree. silver pigeon69 - sorry m8 I dunno, my shooting pal took it to be filled....and his eye's often glaze over in response to questions pressure gauge is on the cylinder whip. Yes, the shop has 300 bar facility (and I'm pretty positive this would have been requested) Quote Link to comment Share on other sites More sharing options...
oldypigeonpopper Posted June 22, 2018 Report Share Posted June 22, 2018 hello, is there not an air rifle shop near you that fills cylinders, or another dive shop, ? if not try make sure its topped up, i use to take my 12 ltr with the guage on and after being filled i put back on to check Quote Link to comment Share on other sites More sharing options...
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