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Downgrading Echo 1 CSR to DMR limits.

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I dry fired it out of the box, but didn't unfortunately run any BB's through it. A definite stupid miss on my part. Hopefully it's as simple as resetting the bucking. I was just so damned anxious to get that new spring in there. Didn't want to get used to having that 500+ FPS and then downgrade and feel all depressed haha.

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Alright, so I apologize in advance for all the photos. But I did promise to show the internals.  ^_^ Just yesterday I went in and completely disassembled the barrel assembly and gearbox to do some compression mods. To say the least, my air pressure is now fantastic. However, Avocado and I discovered that a great deal of air is coming from my feeding nozzle. I'd assume this is due either to a hop-up issue, or a bad connection with the air nozzle. (Did the paper test, and it flew away when laid over the feeding nozzle.) So I'm at a loss if it's a hop-issue, as the bucking is in perfect condition and sealed well. Perhaps the air nozzle is folding over the lips of the bucking or something and creating an air leak? 

 

The simple compression mods include: Floss tying the bucking, teflon taping the hop-up unit to the barrel, stretching the piston O-ring, teflon taping the cylinder head, and adding some teflon around the inner barrel for inner/outer barrel tighter fit. Nothing expensive of course.

 

Also, Obi or Blue, what spring did you go with for the inside of the CYMA? I'm attempting to find a spring that's the same length as stock CSR spring, as the Guarder 130 is too long. I'd rather not cut the guarder to fit as it's FPS would then be too low, and I don't want to change the long term damage to my gearbox.

 

pdtl.jpg

 

 

Here come the other photos:

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Ok. Here it goes. We cut down the origional spring. However what you have on your hands here is a case of an irregular pitch spring vs a regular pitch spring. The irregular pitch spring is the longer one. Its technically not too Long. See they add the tighter coils in the center to soften the pickup on the piston. Also they have a smaller chance of twisting. You will find most after market springs are irregular pitch. I only use Kwa springs Because well I like keeping my internals stock. And they are regular pitch. Also it about has to be the bucking switch it out for something stiffer.

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Ok. Here it goes. We cut down the origional spring. However what you have on your hands here is a case of an irregular pitch spring vs a regular pitch spring. The irregular pitch spring is the longer one. Its technically not too Long. See they add the tighter coils in the center to soften the pickup on the piston. Also they have a smaller chance of twisting. You will find most after market springs are irregular pitch. I only use Kwa springs Because well I like keeping my internals stock. And they are regular pitch. Also it about has to be the bucking switch it out for something stiffer.

Roger. What bucking you and obi go with? The Madbull black? I guess I'll try once again to get that Guarder into the gearbox. Last time I put it in there It shot once, and wouldn't cycle anymore, so I thought that spring length was too hard on the motor. (But it's a powerful motor, so that shouldn't be the case.)

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Your tappet plate or air nozzle may be in a bind making it not slide all the way forward when the gearbox cycles. If this is the case, your air nozzle isn't getting close enough to the bucking to create a good enough seal.

 

Often times when Teflon tape and other things are added around the bucking to create a better seal it makes it very difficult to properly reinstall the barrel and bucking into the hopup unit, usually resulting in the lips of the bucking folding or having the bucking fractions of milimeters away from being fully seated. Just one small imperfection in the lips of the bucking sitting in the mouth of the hopup unit can cause this issue as well as the bucking not being seated into the barrel enough to mate up properly with the air nozzle. Airseal parts are VERY finicky. Once you upgrade one, the rest have to be equally good or the added pressure the upgraded areas produce will overwhelm the weak ones easily.

 

You may try a trick that many DMR builders do almost as an extra measure to help prevent this issue. Get your tappet plate and sand the front of the area bent at almost a 90* angle where the nozzle sits. Only sand a little. Much more than a milometer and the nozzle may sit so far into you loading nozzle that BB's won't feed. If you get it right, the amount you sand off is that much farther that the nozzle will travel toward the lips of the bucking, therefore creating a better chance of a very positive airseal.

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Your tappet plate or air nozzle may be in a bind making it not slide all the way forward when the gearbox cycles. If this is the case, your air nozzle isn't getting close enough to the bucking to create a good enough seal.

 

Often times when Teflon tape and other things are added around the bucking to create a better seal it makes it very difficult to properly reinstall the barrel and bucking into the hopup unit, usually resulting in the lips of the bucking folding or having the bucking fractions of milimeters away from being fully seated. Just one small imperfection in the lips of the bucking sitting in the mouth of the hopup unit can cause this issue as well as the bucking not being seated into the barrel enough to mate up properly with the air nozzle. Airseal parts are VERY finicky. Once you upgrade one, the rest have to be equally good or the added pressure the upgraded areas produce will overwhelm the weak ones easily.

 

You may try a trick that many DMR builders do almost as an extra measure to help prevent this issue. Get your tappet plate and sand the front of the area bent at almost a 90* angle where the nozzle sits. Only sand a little. Much more than a milometer and the nozzle may sit so far into you loading nozzle that BB's won't feed. If you get it right, the amount you sand off is that much farther that the nozzle will travel toward the lips of the bucking, therefore creating a better chance of a very positive airseal.

I might see about sanding the tappet plate, but that seem's like a fairly permanent mod. Afraid I might sand too much. Would also take a lot of testing. 

 

I'll definitely see about buying another bucking or two to test with. Are there any buckings you guys would recommend? Madbull red or black? Or Maybe PDI black?

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The MadBull blue is a stiff enough bucking to take higher FPS. Also MadBull bucking are notoriously thick compared to other brands making them rarely require any added airseal mods. I also really like G&G green buckings. They're actually my favorite. When I first got my G&G M4 about 3-4 years back it was shooting over 420fps right out of the box and the stock bucking handled it in stride. I'm not sure what G&G makes their buckings out of, but they don't react to ambient temps like other buckings do, I.E. get stiff in cold temps and very soft and pliable in warm. Those changes mean you would likely have to adjust your hopup ever OP or game and sometimes in the middle of playing.

 

Which ever you get, turn it inside out and get some super fine grit sandpaper and rough up the nub. This will take the shiny almost plastic looking sheen and smooth surface off leaving behind a rougher more dull looking nub. This will make you hopup more consistent, accurate, and responsive.

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Great comments all around. I appreciate the help guys. 

 

It occurs to me (and if this is the case, I have earned myself one giant FACEPALM) that I may not have been connecting my tappet plate with the air nozzle. Which would completely explain my air leak and loooow power...

 

God I hope that's the case and I've just made a stupid simple mistake... I'll be checking tonight.

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I also recommend the Systema bucking, I've had issues fitting madbull buckings into All my guns. The g&g green bucking is really nice due to being temperature-resistant

 

Not sure how well it'd hold up against the high-fps/heavy bb's but theres also the Modify Flat Hop bucking, it's about $13-15 but it also comes with the nub needed for it too

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hrsp.jpg

 

Alright, so my hunch was right. I reattached the tappet to the air nozzle, and now the thing is shooting like a fuckin' beast. Hop up tests and scope sighting to follow.

 

I did however try the 130 spring once again, to no avail. I believe that even before the motor cycles, the spring is just too condensed, so when the motor cycles, the coils literally compress till they touch and lock up the gears. I'm sure it'd be fine if I cut some coils to shorten it, but I think I might just look for a more compact spring. 

 

Thank's for your help all! From here on it's all about the actual "downgrading" that the thread was originally for haha. 

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Humm well in any case i would just stick with regular pitch springs. If you are looking for a good 130 go to the kwa website and just order one of theirs. or you could just cut your normal one to fps if its over.

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Finally got word back from Echo 1. Sounds like the spacer on the inside of the piston is longer to adjust for the shorter spring length of the stock spring. Going to see about purchasing a normal spacer and that should give enough space for the Guarder spring to fit.

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