WhiteRyder

@Lozart the selector gear was indeed the issue and it's now corrected and working normal. The .28g and .3g both shot with good flight path with my preference being the .3g, seemed to be tighter grouping and I so for the first time I have the mapel leaf with omega nub working in the gun as it should. The range its noticeably better than I've ever achieved, a quick shoot and measure on google earth shows I'm hitting a target consistently at about 50m (with 200mm barrel!) and feel like its reaching past that target I was using by maybe another 10m. Now I'm really happy with the results, cant wait to take it to a field and I think I will be shooting with the same sort of range as the decent guns people have. I will see what the fps is on this m90 spring when it gets chrono'd next and will see if there is room to fit a bigger one. Hopefully the proper lubing (cyclinder was bone dry at last chrono) and replacing the stock cracked piston head with one with ball bearings will increase the efficiency and therefore fps. Appreciate all the quality knowledge and advise @Lozart

I have now ordered some .28g and .3g ammo and see how that goes. Thanks for the idea on the selector gears and plate will give those a look later, looking at it again i bet your right.

@Lozart piston head replaced and put some effort into lubing the entire gearbox and cylinder while in there. The only way I can get the omega nub to not ping off while installing the inner barrel is to put it on the small 205mm original barrel as you can slide it all in together compared to with the longer inner barrel I have to first put the barrel into the gun then put the hopup chamber over it at which point the omega nub pings out even on no/lowest hop setting. Another problem I faced was the original barrels hop window was so badly made the mapel leaf didn't fit evenly so I purchased a 200mm aftermarket barrel so finally I could have a high end hop up system. The original cyclinder was a 1/2 version so left it in as matches the new 200mm barrel better than my 3/4 cyclinder would. Now I have 2 new problems. Is it me or do airsoft problems multiply? First problem is the hopup is too effective as on lowest setting the bb does travel about 30m then drop to floor like it's got no real spin on it but as soon as I add any movement to the hop up slide adjuster it then spins the bb straight up after 20m. It's an overly sensitive but proprietary hopup chamber that isn't letting me adjust it to a useable level. From some research it seems I could try heavier bbs (I'm on .25g) OR I could file down the hop arm part that holds the nub so it doesnt push the nub so far to begin with into the barrel. What do you guys think? The second problem I have is a new one to me, on full auto mode only the gun will usually work on auto but sometimes it will act like it's in semi mode and sometimes it will get very stiff or sometimes just slightly stiff. Video link showing all 3 types of trigger issue within 70 seconds: https://1drv.ms/v/s!AmaoEahXrl4OhII8nS0ut-TLJVWaUg Safe and semi havnt been a problem. What is going on here?!

I have now contacted Pete to see if he can help on the pricing thanks. Will try to remember to come back here to update. Thanks for sharing your knowledge and advice.

I will try cleaning the original barrel and giving that another go (after i get new bucking to suit omega nub and piston head). I read up on the cylinder to barrel length so would use original cylinder with original barrel and would get a 3/4 cylinder to better suit the longer madbull. Just read the ARP9 barrel is 128mm so i get your point the barrel length wasn't the reason he totally out shot me. I will take it apart and get some more pictures, might wait to get the bits i want to replace them before reopening, does this look in line with your suggestions?: https://gunfire.com/en/products/50-aeg-macaron-hu-bucking-green-1152217810.html (i read sub 350fps is best on the 50 degree) https://gunfire.com/en/products/shs-cylinder-type-2-1152196469.html (3/4 cylinder to use with longer barrel, not original) https://gunfire.com/en/products/piston-head-cylinder-head-for-v-3-1152206659.html (piston head is a need and the cylinder head I have looked like nylon with 1 o-ring and looked very well used so think i might as well replace too) The gearbox is a v3 i have and i will get some other bits from gunfire like BB's that I like so worth the shipping.

Loads of sound advice there thanks, I will leave the spring until after the other work I want to do as you suggest. The g&g umg doesn't have blow back so I'm guessing that means I imagined the cylinder hole (but I can picture it in my mind still) if that's made u assume that? If that's the case does the cyclinder suggestion still stand? A new question about barrels then if the accuracy improvement came from quality more than length then would you really think I could get the same accuracy if I had upgraded quality but kept around the original barrel length of 205mm? Not sure you know just how small the umg barrel is that's why I ask I suppose. I'd be tempted by a 205mm good quality barrel if ur pretty sure that much length wouldn't have much/any impact as I could then not need the mock silencer (although it looks cool so might use it in that situation anyway).

Wow I had no idea I needed to pair with the mapel leaf bucking I will get one and try it, do those buckings work with normal barrels like a madbull? The accuracy went up loads when I put the madbull in over the stock barrel so I'm guessing the barrel is not part of the problem. The cyclinder has a tiny hole at top and in centre only about 5mm dia I guess from memory. I feel like it does need a bigger spring as 275 is so far from 313fps limit on .25s. Do you suspect a nuprol 90 should get close to 313 then? Maybe I should try a 95 rather than 100. To clarify in case my previous post was unclear i dont think i am having issues anymore since I worked in the gearbox as i got a 20% ish increase in fps after the work. But saying that yes I do have a crack in the piston head so I will get that replaced, I assume they are universal so something like this will do for example?: https://www.skirmshop.co.uk/action-army-aluminium-piston-head-with-ball-bearin.html Appreciate your help so far.

Tried a G&G green one, now on another brands blue (soft) one and between those and the original didn't notice a flight improvement. I also tried an omega nub but i could only get the bb falling out or jamming, there was no inbetween so gave up and put normal nub back in, another to note was the omega nub didnt fit well into the nub arm so i leterally hot gule gunned it into place so that it woudl stay in there and also so it would reach the base of the arm (the c section that holds the nub is deeper than the nub so it easily fell out each time). The above paragraph was done while I was shooting at around 285fps on 0.25g bb's BUT.... since then i cleaned & lubed the gearbox and swapped the bushings (1 fell out!) and shimmed it and the gun was then shooting at 334fps with same BB's!!!! So i had to buy a 'Nuprol 90 spring' at the site shop to downgrade it so i could play and it now shoots at 275fps with same bb's. The gun was second hand and I had never I done any maintenance before and from the massive improvement achieved i guess the whole time it had a high power spring in it that was just operating very inefficiently due to lack of maintenance from previous owner. I plan to buy and try an M105 & M100 to see which one gets me closest to legal limit. After i have got the FPS back to a better place I will then look at improving the effective range. I have a madbull python 2 barrel at 360mm (hidden under mock silencer) on it during all of the above. I'm not pleased with 40m but love the gun.

That's a shame thanks for the reply. I want to flat hop to get the effective range further out, its currently about 40m with the BB's flight path very much up then down. Using 0.25g bb's on a 'half-gate' size target I have to aim clearly above it. I was stood next to an G&G ARP9 the other day and he put straight shots through a window at 35m~ and I was engaging the same target trying to drop them through the window, was quiet embarrassed with the difference. R-Hop seems more difficult so would try flat instead and im not sure what other options i would have. Also TBH everyone seems to recommend flat hopping as one of the first recommended upgrades.

Hi Guys, I am interested in swapping out the annoying metal hop up chamber with the slide that shifts as you shoot to a better one but im not sure how universal the aftermarket chambers are so i wonder if anyone knows what will fit or what I need to look out for please? I want to flat hop the gun but not with the original annoying chamber. If there are some hop chambers better suited to flat hopping that would be helpful to know too? Original hop chamber is: G&G UMG Metal Hop-Up Chamber Unit G-20-001 and it looks like this:

update for anyone with a similar issue that finds this thread... from replacing the busings and greasing the gearbox and putting back together again the gun went from 285fps on 0.25g bb's to 334fps on the same bb's!!!!!!!!!!!!!!!! My gun was too hot to play with so I had to purchase a spring to down grade the fps so I could play yesterday, lucky they had an on site shop and I had the tools in my car so took it apart on the floor of my car!

Problem fixed. 6 bushings replaced, the remaining 5 were tatty and the shimming was pretty much nonexistent so my probably rookie shimming job should be better than nothing. Greased it up too abit. Gun shoots and sounds nice now. I have spotted a crack forming in the piston so I wonder if it's best to replace now or wait for it to fail if that's still potentially a long way off?

Hi, UMG comes stock with 6mm (oiless) bushings I found out, even the new ones still on sale, my gun is about 6 years old and has fired 10k~ in just the last 6 months alone I quickly calculate from memory. Glad the nozzle position isn't an issue thanks for the info. I did get the gearbox completely open (and have plenty of pictures if you wanted to see them now) and honestly when putting it together again is when I noticed the missing bushing as the other bushings were out of alinement with the case (attached to the gearing still rather than the case). Seems doable from what I have seen and now read on these gearboxes but the shimming process sounds time consuming and with a bearing missing its probably needed as may have had one there. I plan to replace all 6 bearing FYI. Thanks for the advice,

noticed (after taking gearbox further apart, this pic was to help me put everything back in right place) that there is a missing bushing on the gearing behind the trigger as seen in middle of pic. I assume this is the cause of the problem and now have replacement 6mm bushing on order and some shims just incase. Will give gears a tiny bit of grease while in there too.

Thanks for the reply, I dont know anyone with gearbox experience as I'm quite new to the game. I could give it a go myself and follow YouTube, I will have the tools but not sure how much damage I could do with no experience?!