Sitting Duck

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Sitting Duck last won the day on October 2 2017

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About Sitting Duck

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    AF-UK Addict

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  • Guns
    (i need serious help)
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    Camping with lots of ammo/mags
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    Tactical Warfare London/Surrey
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  1. Have you got a spring on hop unit ??? basically the spring ensures the hop is pushed fully back against box to seal better Often if you plug in a mag it "can" bring the hop away from gearbox and result in light contact in this instance light contact means under pressure the lips of the bucking where nozzle seals well it can blow under pressure and there is ya drop in fps Yes the SHS nozzles are usually correct for G&G's but G&G's have that round chunk on the side but they don't always fit a tiny spring on hop unit rip apart an old clicky bic pen or something and polop it on the hop unit's lug/nipple (snigger) Ahem.... or a larger spring just the exact size over the barrel or a couple of o-rings (not springy) to force back the hop unit in place Next time it might be wise to light sand the front of tappet plate (on a table in circular motion) to help the nozzle return a whisker more foward to seal on bucking perhaps reckon you might get the thing to seal up if the hop sits back in place ok There are other factors, on some very new G&G hops the red SHS nozzle can be a whisker too snug/tight fit (think you should be ok though after 6 months) or if the box has been fitted poorly the box can tilt upwards slightly and nozzle can scrape inside hop (basically restricting the nozzle sealing perfectly asap in use) most likely the hop isn't being held back against the front of gearbox with a spring some guns need it more than others G&G sometimes fit a spring - sometimes they don't Just like they usually use bronzey bushings but others they use bearings Also they may use phillips or wtf hex bolts on the gearbox to be ar$ey (jeez I wish they get their consistency sorted)
  2. Of course if you wanna go friggin' nuts you can splash out for gimmicks... Brushless Motors are starting to finally make some inroads - WTF are they are on: £200 - do you know how many crappy guns I could buy with that !!! Well a bloke on fleabay is flogging one for £150 with zero feedback - yeah I'll pass or from here still silly money ffs: French review monsieur : Novatech - didn't they build Johnny Five from Short Circuit Oh no that was was just Nova I think Annnnnnnd VFC are working on some stuff too.... Yeah f*ck all that - think I'm stick with £30 or so motors for now but interesting all the same though ye olde brushed motors are going to be around for a while
  3. If you open up a G&G with very soft bronzey bushings after say 12 months The bushings under the spur and bevel will have considerable wear Look at ye olde plastic bushings and same place spur deffo & under bevel also (they go a bit oval-ated) EVERYBODY will have their own take on crap as I said But under the spur is where the most stress takes place out of all 6 (followed by under bevel but under spur is the #1 area of "possible" wear & failure) IMHO you have two options: #1 steel bushing under spur & other 5 ceramics for max smooth rotation #2 Steel bushings under all 3 gears & ceramics on top - a 50/50 mix of durability/speed either will suffice - you can use half a ceramic set & save/sell the others or keep spares for another build Using #1 of just one bushing on spur will give max rotation and the bushing will lift the spur slightly or the spur on the bushing will only need say a 0.1mm shim and not rub on lower sitting bearings In a 3 x bushing build with little room the spur can slightly rub on the other 3 bushings if shimmed ultra low (I have dremeled the other two bushings a whisker to ensure the very low spur spun freely) Often bushings - I've mixed both regular & cross types leave little room for shim room means you don't get a massive amount of choice when spacing out the gears on bushings vs bearings I've ran out of space with all bushing on chunky SHS spur gear before and dropped a 8mm bearing on top (that gave me a little extra room to shim up with & spin sweetly) Every single build is different & everybody has their own variation or method/reasons they do what they do Yes ceramics are stronger/smoother than std bearings so you should be ok doing all 6 But I had a std 7mm crappy D-Boys bearing box go $hit in 15k and thought F*ck that $hit again (yes 7mm bearings are real crap but the hassle in having to rip it all apart again so soon means sod all bearings) I gladly drop one or two rps on bushings and build it sweetly means very little lost for peace of mind (hopefully) It is up to you what you decide but I'd at the very least consider option #1 if not #2 (guess see how it all starts to fit & shim up once you got the bits together & go from there) SHS gears will do ya proud, Sean Connery has got into teching and is all he uses... OK soz I'll get me coat
  4. Your gun, your build etc.... Infinity motors are superior & Siegetek are of course ergh Siegetek Said many times ask 10 people and you will get at least half a dozen different replies All depends on budget available - I get use same shell in same receiver to ensure exact compatibility etc..... Internals is not just the name/cost but how well it is all fitted together imho Reason SHS motor & gears not just price but many agree they mesh very well together For instance there are two rough basic checks worth performing with bevel & motor/pinion First off all do they mesh at correct angle ? Many stock bevels may mesh ok-ish (some may not) with stock motor/pinion place them both together and try to ensure all teeth are meshing 101% then examine the angle Ideally you want a true 90 degree angle with the teeth meshing fully So that full power is transmitted using all of the available teeth (kinda similar in ensuring correct motor height etc...) If the bevel & spur meshing at say 80 degrees then even set perfectly yoy may only have 75% teeth transmission So in a perfect world you would like to see/feel 90 degree meshing than 95 or 85 degree meshing Extremely bad example pic.... Just coz the two gears actually mesh at perfect right angles means jack though roll the motor/pinion around the bevel and feel how well the teeth actually engage Most of the time decent stuff will work with other decent stuff But it is wise to do a quick check to see that these two foundations of the drivechain mesh great (and roll smoothly as they engage one another) Whatever you decide it is worth give these two gears the once over how they mesh etc... You still got the motor angle/height shimming crap to sort out but it is worth a quick check imho (even if you buy all shs stuff which "should" mesh very well together) If the two gears' teeth mesh at right angle smoothly meaning when the height is set all or nigh on damn it all the teeth are being used to transmit power smoothly how well this all shimmed/set/meshing will result in lower amps & heat/friction genereated (basically cooler gun and battery (as well as build) will last longer) SHS & SHS should mesh well together but no matter what you choose/decide still give it all a quick check when assembling It "should" help to reduce the shrilliness if them bastid gears all mesh sweetly (well that is the theory of it all) Your CNC box should not have a re-enforced arc on top of spur so you can fit higher speed gears in than be limited to 16 or 18:1 (or require a dremmel mod to fit 13:1's in there) So fit what you like 13:1's is fast enough though Most 16:1's are actually 17.25:1 and not worth upgrading for speed from a std set (ok if building from scratch but not a great improvement over 18:1's (18.65:1) Have a think, decide for yourself as it is your gun just perhaps check how well the two actually mesh smoothly
  5. Agreed: SHS/RA Motor & gears will do you proud for a modest 20-24rps build you could hit say 20rps on the SHS Torque (really a balanced motor than a slow ultra torque) with 18:1 gears or you could hit say 24rps on the SHS Torque with 13:1 gears These are ROUGH ball-park max figures on bushings so ceramics add a couple of rps you could most likely use 16:1 with ceramics & get near the performance of 13:1 All figures will depend on motor - shove in a slower way torquey motor like 22tpa Or use a titchy burst rating 15-20c then rps will be lower You could use 13:1's then use Titan to tweak the final setting - ask Hangtight As for all ceramics - perhaps consider using just one bushing under spur... Just long durability where all the stress forces meet in the drivechain Apart from that reckon SHS gears with SHS/RA motor will mesh nicely as is And be more than up to the task
  6. Best thing is to read the tutorials/guides in the beginners section first perhaps In case it fails to display in my sig.... New players - please - pretty please read the guides first in New Players Section An absolute must read is this one: & plus a search is less keystrokes that creating same ol' new posts again & again - what to buy etc.... Most stuff will be covered I would say, LOADS of info, wish I found this before (made a few bad first purchases and wotnot - could have avoided that if I read up first) Glance over the guides if you still have a question then ask away sir PS - welcome to the forum
  7. Cheers - so it means that 53.5 distance if we take off 20 in total or so will give perhaps 335 @ on about 2.0:1 or a bit more vol on a slight shorter barrel or take off a bit more in calculating prior to x10 for higher volume heavier bb's So even my revised 12 to 15 seems incorrect if you seek a 2:0:1 ratio 15 might be ok for 1.75:1 volume but shooting tests might still not be ideal (like I said some of the stuff written like 1.47:1 ratio I thought was way too low tbh) as yourself & Hangtight find a ratio of 2:0:1 upwards better then perhaps the subtraction figure or Y needs to be 20 or a bit more X = port distance Y = value to subract (15 for 1.75, 20 for 2.0 or 25 for for 2.25:1) Z = barrel length (X - Y) x10 = Z (kids remember brackets or equation will be wrong as multplication takes priority over addition & crap) F*ck me my head hurts - this was supposed to simplify it but as per usual I've made way more complicated than it needs be
  8. I would have said 53.5 - 15 = 38.5 x 10 = 385 cylinder port would ok to use for up to 385mm barrel That was what I did the rough ready for What I'm trying to do is say we increase the amount to subtract (originally about 10mm is where the piston head rests on cylinder head) SAY we did 53.5 - 20 now = 33.5 then x 10 = 335 then this would be the newer setting to use up to a barrel length of 335 with a higher barrel/vol THIS is why I'm asking Hangtight to display his port position OR if you can list the length of your barrel in the SCAR perhaps This way it can refine or improve a rough ready guide for say a decent-ish 2.0:1 guide without going done the calculation route or trying a shorter barrel to improve the vol I'm just trying to see if the rough guide subtraction amount or Y or whatever can helped to be refined that was all To sum up you took off say 10 where head+sorbo was then took off 11 then x 10 etc.... What I started with was just 12 only then went to 15 to subtract there was only really one figure to subtract then x 10 etc..... (just to keep it as simple as possible I guess) I then revised this to 15mm (still lower than your 21 (10 then 11 subtraction) as 12mm was producing say 1.65 ratio so 15mm produces a more 1.8 ratio Which according to some guides is acceptable but I have reservations.... according to this even 1.42:1 is acceptable but I think that is bollox on PDI AK47 hence me trying to push for 1.75-ish at least or 1.8:1 with revised 15mm number to subtract now if that needs to increase to (X - 20/25) x 10 = ideal barrel for a 2.0:1 then fair do's Now with both your gun & Hangtight's testing you are happy with a a ratio of 2.1 - 2.25 ish Soooooooooooo if you inform us of your barrel in SCAR & Hangtight posts the pic/dimensions of his cylinder porting THEN it might be a straightforward of say 53.5 - 22.5 or something = 310 x 10 = 310mm barrel eg: sunbtract 15-ish for 1.8:1 ratio 20-ish for 2.0:1 ratio 25-ish for 2.2:1 ratio see what yields best results in shooting or proof of pudding then it might provide a fairly accurate rough/ready guide in seconds than try to enter & calculate all the variables cylinders don't vary that much and tbb Vs reg decent barrel of say 6.05 or bore up kits do not effect the final vol results THAT much excluding very wide bores or AEP cylinders most stuff is within a regular margin but the stroke just by a couple of mm can start to impact ratio a fair bit so trying to put or refine an easy checky thingy majig based upon port position etc...
  9. Long story short.... One day if/when you get a chance, pop the top receiver say Then take a pic maybe of port with the dimension of front of cylinder to port Basically the front of cylinder to red line or front end of port please if you can We can call this distance X before we get into geeky world Just trying to see if the amount to subtract from X is 10, 12, 15 or so before multiplying by 10 More trying to see if my theory works out and if we can use a rough ready reckoner Than a calculator or app A good one is here: Compression Volume Calculator/ because you can mess about with figures and ratio updates as you adjust crap The stroke of 60mm might be an absolute max on AoE it could be 58 at a smidge over 12 o'clock (normally it is about 12:30 position but everybody has their acceptance of total perfection or acception) A non AoE piston you got say 4mm or so extra stroke making 63 or 64mm stroke The stroke even just a couple of mm will effect volume possibly more than any bore up kit (mess about in calculator and see it do its maths magic on exact same gun) hence to DMR mofo's sinking money into bore up kits, probably best just partially correcting AoE Anyway - soz for waffle, great test - if you get a chance post a pic with dimensions of port to cylinder head then I/we might have idea what to take off in a rough ready reckoner (please - with sugar & cherry on top)
  10. depending how boned any gun is..... generally I'd say buy new and keep oldie for parts/spares thing is you could get a new better receiver, f*ck about trying to swap bits about... Then find out receiver has slight/major compatibility issues Now in most cases you "should" be ok but you need to prepare for at least slight modding Therefore, I suggest you consider maybe looking at at a new gun at a good price to avoid "potential" grief Not saying don't replace/repair but pointing all the possible issues & factors to consider At least you will have a working gun on delivery PLUS most importantly.... MORE GUNS - (not ANOTHER f*cking gun Mrs Duck says (forgetting the girly shoe mountain))
  11. It depends on a few factors - you can correct the AoE perfectly or slightly over-correct or under-correct The Correcting of AoE bang on or smidge over/under "can" effect the stroke/volume more than any bore-up crap imho On the piston's release it is completely static,will need to accelerate to final speed the o-ring hasn't even begun to seal let alone compression starting to build properly So there must be a good 5mm of travel before any power is actually generated Hence I gave it a few more mm's to allow for the power to build from nothing As I say it open to everybody's take on stuff and stuff will vary but the maths of cylinder barrel ratios even on a easy to use online airsoft calculator or a tiny little app is open to variations or interpretation or perhaps I think hmmm nahhh I just noticed there was some correlation to gear ratio checking and also the dimension of the port to barrel it is supposed to be paired with tweak it all how you see fit but just gave a rough basic guide to consider as a foundation perhaps nothing I ever say should be taken as 101% Gospel as I often talk out of my ar$e Plus we are ALL still learning with every build - so nothing I say is set in stone
  12. A G&G SR25 has a std cylinder not a proper longer 2.5 cylinder like SVD & L85 19 tooth thingy's In THEORY they should only be using a 455mm barrel in that sense But they can use a 510mm if setup REALLY WELL but it is pushing the volume imho Ideally for say 550 barrels you will need a longer cylinder like the v2.5 SVD L85 But even then I would not go beyond 610 barrel The volume thingy is still open to debate but the general guide is to stick with an aprox vol ratio (depends on bb weight but again it will vary a little plus the odd one that works but perhaps pushes limit) TBH I stopped studying this stuff way too much, it is open to everybody's take and instances that break mould I got a rough - and I say rough idea or method to avoid doing PhD maths n crap on gears & cylinder/barrels It seems to kinda work (so far) so I'll still continue to use an easy rough n ready reckoner on very short (mp5k) or very long (AEG SVD/L85) the correlation may not be 101% perfect but in general it works (well I think so - so far)
  13. Soz to crash but have I read the cylinder window (12mm) is 48mm from front ??? subtract 15 from 48 = 33 & multipily by 10 = 330 330 is a rough guide to matching up barrel lengths to cylinder (giving you aprox 2.0:1 ratio dooberry give or take a smidge) NOTE NOT 12MM BUT TAKE OFF 15MM FROM 48MM = 33 OR 330 BARREL AFTER X10 see here but the post I created a while back at the very end I revised the 12mm figure to 15mm (basically to allow a bit more I found for piston releasing & pressure to start building) WARNING - NECRO POST ALERT !!!! Those volume ratio calculators & even the pic of cylinder ports to M4 carbine are a bit confusing plus the 2/3 or 3/4 or 4/5 bollox is open to interpretation I thought at times - sod measure, minus 15 & x 10 Same as gear ratio malarky counting/pulling teeth - just multply the bevel turns by 3 than f*ck about loads Not quite 101% of exact volume ratio this (X -15) x10 method gives out At time of writing I was guessing @1.6 maybe 1.7 then this forced me to revise to 15 not 12 Still a bit sad looking at things in my OCD way but not quite as bad as I used to (the medication is at last starting work) Anyway good guide/test results sir especially the figures and levels of fps variation nice one
  14. Don't bother imho At first they seem like the ideal stop gap between 7.4v & 11.1v BUT from my experience they don't offer any real improvement over a decent 25c or 30c 7.4v lipo They are more expensive, very limited options due to very very limited range AND they MUST be charged differently to lipo's Each cell is 3.3v with a max rating of 3.8v I think If you use lipo settings of 3.7 or max 4.2v you will damage LiFe's So you need to setup the charge settings in say a B6 charger Or ensure you have a V3 type charger (balance lead) that has a proper LIFE port Seriously, when I have compared a 9.9v life to a 7.4v 25c I noticed no difference at all They are bulkier as they are 3x3.3v cells compared to 2 x7.4v More expensive and just not worth the hassle imho If you got a decent motor say the 30k Krytac motor then 7.4v should be plenty If you got the 20k then just use 11.1v
  15. If motor turns on its own then it is likely the box has locked up - most probably due to a part failing In rare daft cases if polarity is incorrect the box will attempt to run backwards but be stopped by the Anti Reversal latch BUT you said it was working ok so I guess you didn't mess with stuff before As long as you have the red wire to red motor pole or + symbol on the blue motor and red goes to red etc..... Then you can rule out reverse polarity so it looks like box has seized or locked up It could be a spring caught up on retraction or something simple but tbh I doubt it G&G's are "normally" built quite well but over time and this is s/hand so could be lightly used or well abused Likely something like bushing/bearing failure or AR latch or even a small chunk of plastic/metal broke off wedged in gears (you wouldn't believe how a small piece of crap can lock up even a beefy drivechain system) Doubt if it is a knackered piston - normally shredded pistons or snapped at back just make a ZZZZZZZ sound You have a locked box it semms - so something has failed and jammed up the box real good - it ain't turning Now it could be this or it could be that perhaps but I still feel it is going to need tearing open to investigate then diagnosed and serviced/replace any parts showing failure or wear then regreased and reassembled & test I've given you a tech or ask your local site to perhaps investigate shouldn't take long or cost a silly amount to sort out I'd like to help but got some stuff on my plate already Also Mrs Duck wants the dining table clear of bits n bobs for some Turkey dinner thing on Monday (yeah kinda weird these women I know but I think she really means it this time)