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AEG first shot dropping short??
- Thread starter rschris
- Start date
Ian_Gere
Retired Moderator
- Apr 1, 2012
- 6,417
- 2,050
Yeah, I'd guess the seal between nozzle and hop bucking, or perhaps the buckig being too stiff and poking into the barrel obtrusively.
It could also be the piston O-ring only working after it's been reseated by the piston being pulled back. Someone told me a good trick is to heat the O-ring and strretch it over the cylinder to make it fit more tightly inside. I haven't tried it yet so I can't add my yay or nay right now. You could try more grease or oil on the piston head though, which I can recommend, to make the O-ring more slippery so it doesn't get pulled tight towards either the front or rear of the cylinder.
It could also be the piston O-ring only working after it's been reseated by the piston being pulled back. Someone told me a good trick is to heat the O-ring and strretch it over the cylinder to make it fit more tightly inside. I haven't tried it yet so I can't add my yay or nay right now. You could try more grease or oil on the piston head though, which I can recommend, to make the O-ring more slippery so it doesn't get pulled tight towards either the front or rear of the cylinder.
Airsoft-Ed
Retired Moderator
- Nov 7, 2010
- 4,164
- 941
It sounds like a hop issue to me.
First shot is getting blocked by the hop but bashing it out of the way, following shots are ok because the hop was shifted by the first.
If you leave it a while then the hop will drop back into the barrel and block it again, it's happened to me before with my L85.
If it were something to do with the air seal it would drop short with every shot. Get the hop unit out and dismantle it, the spring that pushes the bucking down might be sitting wrong in the unit or something. Get the hop and barrel out and look down it, check for protrusions. Just because the hop wheel says hop is off, doesn't mean it is.
First shot is getting blocked by the hop but bashing it out of the way, following shots are ok because the hop was shifted by the first.
If you leave it a while then the hop will drop back into the barrel and block it again, it's happened to me before with my L85.
If it were something to do with the air seal it would drop short with every shot. Get the hop unit out and dismantle it, the spring that pushes the bucking down might be sitting wrong in the unit or something. Get the hop and barrel out and look down it, check for protrusions. Just because the hop wheel says hop is off, doesn't mean it is.
Airsoft-Ed
Retired Moderator
- Nov 7, 2010
- 4,164
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I don't know enough about the intricacies of the SRC hop units to understand how that would deem me wrong, from my experience it sounded like a hop issue.
Hudson
Members
- Oct 9, 2011
- 787
- 381
Possibly a Tappet/Gear issue?
It's not cycling properly, so only getting half a cylinder's worth; hence the low range/power?
Had similar issues with a couple of my guns; which I solved by either replacing the tappet plate or putting a delayer chip on the sector gear. Although with mine it was normally something like every fifth or sixth shot, not the first one.
It's not cycling properly, so only getting half a cylinder's worth; hence the low range/power?
Had similar issues with a couple of my guns; which I solved by either replacing the tappet plate or putting a delayer chip on the sector gear. Although with mine it was normally something like every fifth or sixth shot, not the first one.
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Airsoft-Ed
Retired Moderator
- Nov 7, 2010
- 4,164
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I think I'm now having the same issue with my L85, except the frequency of it isn't restricted to the first shot only, it happens on and off, a lot.
For me it looks as though the hop is suddenly being turned completely off. It goes from flying straight for about 60m, to dropping short and landing at about 15m. In fact it's kind of like the hop swivels 180 degrees.
I've no idea what it could be either, 'cos it certainly isn't the hop unit. I'm getting absolutely perfect compression in the cylinder, so it's not that either. My only thought is that maybe the gears are slipping occasionally at only half cycle... I've no idea why they would do that, but that seems to be what the effects show. The sound it makes suggests something similar as well, when it's shooting properly, it sounds normal. But on a shot when the range drops it sounds like the motor is tightened too far into the gearbox, it makes a slightly more whirry sound than normal.
Having said that though, there's only minor wear on the piston and the gears all look new, looking into the magazine well also shows that the tappet plate is functioning perfectly, meaning the gears must be cycling properly, so I've literally no idea what the hell is wrong with it... But god I'd like to... It's truly typical of my luck for my gun to start behaving like this just as soon as I've got it finished externally <_<
For me it looks as though the hop is suddenly being turned completely off. It goes from flying straight for about 60m, to dropping short and landing at about 15m. In fact it's kind of like the hop swivels 180 degrees.
I've no idea what it could be either, 'cos it certainly isn't the hop unit. I'm getting absolutely perfect compression in the cylinder, so it's not that either. My only thought is that maybe the gears are slipping occasionally at only half cycle... I've no idea why they would do that, but that seems to be what the effects show. The sound it makes suggests something similar as well, when it's shooting properly, it sounds normal. But on a shot when the range drops it sounds like the motor is tightened too far into the gearbox, it makes a slightly more whirry sound than normal.
Having said that though, there's only minor wear on the piston and the gears all look new, looking into the magazine well also shows that the tappet plate is functioning perfectly, meaning the gears must be cycling properly, so I've literally no idea what the hell is wrong with it... But god I'd like to... It's truly typical of my luck for my gun to start behaving like this just as soon as I've got it finished externally <_<
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Airsoft-Ed
Retired Moderator
- Nov 7, 2010
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But the tappet plate isn't at fault, the gun is feeding perfectly, there's also no cracks or wear visible on it either.
I'm adamant the tappet plate has nothing to do with it.
I'm adamant the tappet plate has nothing to do with it.
Airsoft-Ed
Retired Moderator
- Nov 7, 2010
- 4,164
- 941
I guess there can be times where airsoft related issues simply defy physics, I've had my fair share of those experiences... I'll have to look into getting a new tappet plate then. I'm selling my M16 to get cash to go to town on the internals of my L85, so I might as well spend some of the dosh on replacing the tappet plate.
Think I might get a new piston as well whilst I'm at it. Might as well lol.
I didn't mean to come across as snide or rude before, I meant no offence. The tappet plate just really didn't seem to be the culprit.
Think I might get a new piston as well whilst I'm at it. Might as well lol.
I didn't mean to come across as snide or rude before, I meant no offence. The tappet plate just really didn't seem to be the culprit.
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Hudson
Members
- Oct 9, 2011
- 787
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It didn't with mine, either! 
It had me absolutely stumped for ages; On my Beta Spetsnaz I changed the barrel, the bucking (several times), the nub, the unit, the nozzle, the gears and none worked!
Had the tappet plate suggested to me, and it worked straight off after that and never did it again... (Touchwood)
Then when the same problem happened to my SR25 (Due to not able to get my hands on a tappet plate easily) I used one of the Sector gear delayers and that sorted it too!
It may very well turn out to be something different but if the hop's not at fault, then it's definitely worth looking at; from my experience!
It had me absolutely stumped for ages; On my Beta Spetsnaz I changed the barrel, the bucking (several times), the nub, the unit, the nozzle, the gears and none worked!
Had the tappet plate suggested to me, and it worked straight off after that and never did it again... (Touchwood)
Then when the same problem happened to my SR25 (Due to not able to get my hands on a tappet plate easily) I used one of the Sector gear delayers and that sorted it too!
It may very well turn out to be something different but if the hop's not at fault, then it's definitely worth looking at; from my experience!
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Airsoft-Ed
Retired Moderator
- Nov 7, 2010
- 4,164
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Managed to sort this out the other day - no new parts required.
My piston head wasn't working right, my AOE was off slightly. My piston head has a little protrusion in the centre that enters the nozzle, which creates an air cushion at the from of the cylinder. So even though it's an aluminium piston head, it's perfectly cushioned and actually quite quiet.
But the protrusion was hitting the edge of the nozzle instead of going into it, then the gears were grabbing the piston half way along, instead of at the end.
The result was a horrible noise and a massive drop in compression. Altering the AOE slightly and set the gears up right and now it's fine.
My piston head wasn't working right, my AOE was off slightly. My piston head has a little protrusion in the centre that enters the nozzle, which creates an air cushion at the from of the cylinder. So even though it's an aluminium piston head, it's perfectly cushioned and actually quite quiet.
But the protrusion was hitting the edge of the nozzle instead of going into it, then the gears were grabbing the piston half way along, instead of at the end.
The result was a horrible noise and a massive drop in compression. Altering the AOE slightly and set the gears up right and now it's fine.
Airsoft-Ed
Retired Moderator
- Nov 7, 2010
- 4,164
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Angle of engagement.
It's to do with how the sector gear and the piston engage. The angle part is down to how far along it's rotation the sector gear meets the piston.
My sector gear's first tooth is at about the 11 o'clock position of it's turn when it meets the first (or last, depends on how you think about it) tooth on my piston.
You adjust the AOE by padding the front of the cylinder so that the piston sits further back, or by adding washers/spacers between the piston head and piston...
Tbh I find that the AOE tends to just make itself work, I don't think it's all that important. But this piston head I've bought needs it to be spot on, otherwise it causes the piston head to hit the cylinder head wrong...
...I'll have to show you some time haha.
It's to do with how the sector gear and the piston engage. The angle part is down to how far along it's rotation the sector gear meets the piston.
My sector gear's first tooth is at about the 11 o'clock position of it's turn when it meets the first (or last, depends on how you think about it) tooth on my piston.
You adjust the AOE by padding the front of the cylinder so that the piston sits further back, or by adding washers/spacers between the piston head and piston...
Tbh I find that the AOE tends to just make itself work, I don't think it's all that important. But this piston head I've bought needs it to be spot on, otherwise it causes the piston head to hit the cylinder head wrong...
...I'll have to show you some time haha.
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