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Downgrading Echo 1 CSR to DMR limits.

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Guest Specs

Hello AMS community! 

 

I find myself in new territory here, as I am no mechanic, grease monkey, tech, or engineer. Prior to ESR 19 in March, I plan on stepping up from my meager A&K SVD to the Echo 1 CSR. However, the platform comes shooting at a steady 500-510 FPS, and I of course need to bring that down to the -450 range for DMR applications. So as I'm researching different springs, it looks as if I'm in the market for an m120 or m130.

 

My concern is that the CSR comes with a 685mm Inner Barrel, which I'm fairly certain will increase my FPS beyond the standard range shown for those springs. If that's the case, should I go with the m120? And are there any brands in particular you all cling to? I hear decent things of the Guarder and Echo 1 (piano wire) variety. 

 

Thanks for your time everyone. I'm both intimated and excited to open up and get hands-on with my first AEG platform.

 

 

 

-Specs of Ozark Mountain Milsim

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685mm?! :blink:   That's just crazy! I would hope the voume of the cylinder is equal to or greater than the volume of the barrel, otherwise you will have to rely on a heavy spring to sling that BB out before suffering from the dreaded 'suck back'. I would go with an M130. With the M130 you can test it out and if you're a little over, you can always clip off a coil or two until you get down to the desired muzzle velocity.

 

I've used Echo1 and Gaurder both. Both were good but the Echo1 showed more of a drop in velocity once is 'settled in'. I've had several Gaurder springs in several guns and holy cow do they hold their tension over years and years of use.

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Guest Specs

Thanks for the response Metal! 

 

Yeah, that barrel is a tight squeeze to be sure. But I hear the consistency over distance out of the box is incredible. Provided I had access to a chrono (I guess I could go to my local field to use theirs), that'd be a great plan. I'll have to hunt a spring down. I just want to be sure it's all fieldable prior to getting to ESR, realizing I'm a good deal over 450 after all, and having to open the bitch up minutes before the event starts to do the deed. 

 

The sheer amount of screws makes opening the CSR a pain. I just don't want to pay some asshat $30 just to swap such a simple part.

 

Also, is there a soft FPS cap at that 450? If I came to ESR and chronoed at say... 455 consistently (albiet not purposefully), would there be some leniency there? Or will I be required to make changes? <--- Though that might be more a question for someone of JP's status.

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try a fluted barrell.. you can keep the power but it has slits pre cut in the barrell to allow you to meet chrono specs, also its a tbb so you wont lose accuracy. 

Not a bad idea either! Assuming I can find a long enough barrel to fit the CSR. It's a looooong platform.

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Mine has a M130 that's had 2 coils removed. Shoots 440 consistently.

Oh man! I forget you have an SVD as well. You have the CSR model from Echo 1? Or the CYMA brand? The internals are a tad different, so just making sure we have the same power and such. Did you have to treat the end of your spring at all if you cut it? And what brand spring did you go with?

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How many rings can you clip though before the spring would simply be too short to function?

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A LOT! most springs are about twice the length of the cylinder. However I believe that the rate at which a spring looses fps is about 10-15 fps per loop. So cutting it too short to function should not be an issue. But whatever you do make sure the spring is flat at the end. If you don't more than likely it will twist during use and break. And that is no good for anyone.

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Mine has a M130 that's had 2 coils removed. Shoots 440 consistently.

Any idea if Matrix and CYMA are the same company? I'm not seeing any CYMA brand SVD's on Evike, only Matrix's, and it seems as if they make Identical AK's. 

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Well, to be safe regardless, I just put in my order for the Echo 1 Model along with a Guarder 130. Looks like I'll have to find a chrono nearby for me to text the coil cutting process. People claim it pushing out 430 FPS however, so maybe I'll be sitting at a decent number. Just have to see what that loooooong barrel adds or takes away from it.

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Alright, so the CSR came in, and I bravely jumped into the gearbox and tried for the spring swap. Immediately following assembly, BB's simply rolled out of the barrel on firing. No force, but the gearbox and everything else seemed to function as it should. I opened it back up, put in the old spring, and tried to tighten down the piston head thinking it was an air seal issue. Fired again after assembling again, and now shots maybe travel 10 feet. I'm at a loss here...

 

Battery is both fully charged and new, nothing is wrong with the hopup or barrel assembly, motor is all kinds of strong, and all gears and parts seem to be as it came when new inside the gearbox. I'm still thinking it's a compression issue, but I have no idea where anything would be escaping as the piston isn't ported, and they seem to fit snuggly within the cylinder.

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I'll put an order in for a new bucking then. Is there any methods to better that seal between air nozzle and barrel as well? Teflon tape perhaps? 

 

I've also heard of people flipping the cylinder head and stretching the piston o-ring a tad for better seal. Not sure what the long-term ramifications on that would be however. 

 

What bucking does Obi have in his? The CSR came with an orange madbull, so I'm a bit surprised that there'd be any issue with it.

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We used a madbull black. I would be very skeptical about that being a madbull. Usually when you have bbs rolling out of the barrel like that it means you have a bad bucking or Its pulled too tight over the barrel. Most svds have an issue with dubble feeding as well as said issue. As far as air seal between the hopup and nozzle. There is really nothing you can do. As all those Parts are screwed in place. I wouldnt put tape anywhere near any of those Parts you are just asking for trouble that way.

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We used a madbull black. I would be very skeptical about that being a madbull. Usually when you have bbs rolling out of the barrel like that it means you have a bad bucking or Its pulled too tight over the barrel. Most svds have an issue with dubble feeding as well as said issue. As far as air seal between the hopup and nozzle. There is really nothing you can do. As all those Parts are screwed in place. I wouldnt put tape anywhere near any of those Parts you are just asking for trouble that way.

I'll take that barrel assembly apart and check firsthand, but that was one of the documented differences in the Echo1 rebrand of the CYMA model was the madbull orange bucking. 

 

I've also been scouring some other compression forums to see about other things that might go wrong. My first big concern is that my cylinder might have been flipped by accident. In which case (assuming my cylinder is ported and I simply didn't notice), the porting is facing forward and therefor losing a ton of air. I'll open up the gearbox when I get home to confirm that as well.

 

On the teflon tape issue, I was more or less referring to the bucking/barrel seal. I see a lot of guys tape the forward half of the bucking to the barrel to seal off air there, and sometimes even the hop-up unit to barrel assembly where possible. Some guys even prefer to do that method with floss rather than the TT. This of course all hinges on the theory that the bucking is indeed fine. It may be in alright condition but wasn't seated properly or something. It could probably use a little silicon spray regardless.

 

Next time I open her up I'll be sure to take a good deal of photos as well so you can all have eyes on it. I'd really rather not have to ship this thing somewhere else if I can solve the issue myself. Not to mention my thirst for victory on this matter.

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Ahh I see I have done this with teflon tape before. Havent needed to in a long time.

 

I am willing to bet that the bucking is pulled too tight over the barrel tho. Mainly because this kind of issue usually occurs Because the bb is not held in the chamber. As in if the bucking is allowing it to pass without much force. You sometimes get the same effect if there is too much oil on the bucking.

 

Did it fire ok right out of the Box?

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