F2help Posted July 27, 2020 Share Posted July 27, 2020 Hi, I recently purchased a F2 engine - since purchasing I have had problems with not being able to achieve 1J of FPS, this is while using 120psi, 99dP too. What I have tried to doing to resolve - change inner barrel (almost doubled the length, is now 250mm), got a different hopup rubber (unrelated), fixed my regulator (separate issue), corrected alignment of the engine, tried using closed bolt mode, tried a different hopup unit/inner barrel combo from a different gun I own (it had an even longer inner barrel but made things worse). This is incredibly frustrating as I have owned this for about 2-3 weeks by now and haven't been able to field it once. Hope someone can help! Link to comment Share on other sites More sharing options...
Supporters Adolf Hamster Posted July 27, 2020 Supporters Share Posted July 27, 2020 what gun is it going in? the f2 will be as sensitive to nozzle length as an aeg, so whilst *most* m4's and ak's are probably ok with the stock nozzle, if it's in something more esoteric, or there's some other problem with the hop unit/nozzle alignment then you can get air leakage. way to test for that is to see if you get air coming down the feed tube when firing, needless to say the perfect scenario is all the air going down the barrel. i'm finding around 75-80psi is what i'm needing to get 1j on 0.32g ammo out of a 250mm barrel (and that's with a low-flow poppet) so i'd be inclined to think there's definately a leak somewhere. Link to comment Share on other sites More sharing options...
F2help Posted July 27, 2020 Author Share Posted July 27, 2020 2 hours ago, Adolf Hamster said: what gun is it going in? the f2 will be as sensitive to nozzle length as an aeg, so whilst *most* m4's and ak's are probably ok with the stock nozzle, if it's in something more esoteric, or there's some other problem with the hop unit/nozzle alignment then you can get air leakage. way to test for that is to see if you get air coming down the feed tube when firing, needless to say the perfect scenario is all the air going down the barrel. i'm finding around 75-80psi is what i'm needing to get 1j on 0.32g ammo out of a 250mm barrel (and that's with a low-flow poppet) so i'd be inclined to think there's definately a leak somewhere. Thanks for the response dude! It's going into an ARP556 so shouldn't be anything crazy. When I fire it without the mag in, I can feel a pretty significant air come down the magwell - I indicated this in a post elsewhere and I was told this was normal, is this the opposite and is actually the problem? If so, any idea how I would go about fixing this? Is it a case of the nozzle not being 'far enough' out of the gearbox to make good contact with the hop up rubber or something? Thanks again for your help! Link to comment Share on other sites More sharing options...
Supporters Adolf Hamster Posted July 27, 2020 Supporters Share Posted July 27, 2020 6 minutes ago, F2help said: Thanks for the response dude! It's going into an ARP556 so shouldn't be anything crazy. When I fire it without the mag in, I can feel a pretty significant air come down the magwell - I indicated this in a post elsewhere and I was told this was normal, is this the opposite and is actually the problem? If so, any idea how I would go about fixing this? Is it a case of the nozzle not being 'far enough' out of the gearbox to make good contact with the hop up rubber or something? Thanks again for your help! hmm, i agree an arp556 shouldn't be too much of a problem for fitment. i'd take a look at both the hop bucking (specifically feed lips) and possibly the hop mounting (ie maybe the whole hop unit is sitting forward) pretty normal to use a spring/silicone tube/bunch of o-rings in front of the hop unit to make sure she's pressed nice and tight to the gearbox. Link to comment Share on other sites More sharing options...
F2help Posted July 28, 2020 Author Share Posted July 28, 2020 23 hours ago, Adolf Hamster said: hmm, i agree an arp556 shouldn't be too much of a problem for fitment. i'd take a look at both the hop bucking (specifically feed lips) and possibly the hop mounting (ie maybe the whole hop unit is sitting forward) pretty normal to use a spring/silicone tube/bunch of o-rings in front of the hop unit to make sure she's pressed nice and tight to the gearbox. Update on this - I installed the older hop up rubber that came with the gun (G&G blue I assume) and now air no longer comes down the mag well when firing. Now a different issue has came up... my gun jams pretty much straight away after the first/second shot in the hop up unit. What is the cause of this? And how could I go about fixing it? Link to comment Share on other sites More sharing options...
Supporters Adolf Hamster Posted July 28, 2020 Supporters Share Posted July 28, 2020 3 hours ago, F2help said: Update on this - I installed the older hop up rubber that came with the gun (G&G blue I assume) and now air no longer comes down the mag well when firing. Now a different issue has came up... my gun jams pretty much straight away after the first/second shot in the hop up unit. What is the cause of this? And how could I go about fixing it? What kind of jam? If its just not picking up a round then you could look at increasing dn to give it a bit more time to let the bb up from the mag Link to comment Share on other sites More sharing options...
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