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Stronger springs cut for 350 fps?


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Exactly what it says on the tin....has anyone tried for example, cutting down an M120 to give 350 fps. I'm curious.

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Something like that. But I'm also wondering if you can reduce the piston impact on the cylinder head by accelerating the piston harder at the start of the stroke using a stiffer, shorter spring with less preload on it.

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Yes. I do have a stupid amount of springs around so many times I cut them down to get the needed fps. I haven't noticed much difference.

Don't go too short with it and you're good.

I don't think it matters on the impact. Probably it is easier for the motor to start the cycle because there is indeed less preload. And it's easier to put it into a quick spring change gearbox.

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Problem lies in that the spring might be too short.

 

I used to cut about 3 or 4 coils off M110 springs to bring them down to 340FPS on the G&G Pneumatic blow back guns.

 

Worst case was an old (about 10 yers old) TM P90 i had, i got it for free, cleaned it up and put a M100 spring in it. Clocked in at 370FPS :o

 

So i had to install a M90 spring in it and cut a few coils off it to bring it down to 340FPS on .20g BBs, fast ROF gun i ever had 30+ RPS on 11.1v Lipos

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I have cut down many springs to lower the fps but I always heat the ends with a blow torch whilst pressing against a hard surface, so that the spring seats as it should, and as has already been quoted not too short. Just cutting the spring and fitting it is pretty naf really as it doesn't sit right and you will get irregular fps

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If/When you come into some cash buy yourself a APS UAR

 

http://www.taiwangun.com/en/electric/urban-assault-rifle-black-aps?from=listing&campaign-id=20

 

Best spring tester out there, fastest spring change I know under 30 secs

(did have 10% off last week like a lot of stuff at TWG)

 

I have got about half a dozen or so springs tested with a bit paper wrapped/stuck on them

tested the fps both ways if irregular type so got a rough idea of what is what from hot guns

 

Any hot/warm gun I can pull the spring out & test in UAR then select another 15-20 fps less

Takes a bit of guesswork out of it all and does work fairly accurately considering

I say fairly accurately coz if you improve seals, correct AoE, spring guides, spacers ShortStroke etc...

Well it will throw up other factors into the mix of course blah x 3

 

I don't normally cut springs - only time I've bothered to cut a spring is cutting off ye old hook bit

A new m100 or M105 is only about £7 in the end

I'll tend to use the warmer springs in say 300mm guns or less and SS a tooth maybe if needed

 

I tend to reject springs that are too short say less than 150mm

normally a v2 box is about 160mm aprox in length - if spring is shorter than box I'll tend to bin it

Mainly coz I feel really short springs have less tension as piston releases and doesn't slow piston much

I feel that a light shorter spring having less tension in early stages of retraction contributes to overspin more

(probably no way as bad as I assume but that is just me being a tart)

In general I aim for about a 160mm to 170mm spring length not less but that is just me being a tart

 

Some springs can be a tiny bit tight fit over the spring guide or inside piston blah x 3

If in doubt just buy a new spring of better material than some cheapo china guns

They don't cost the earth in the end but a UAR is great little gimmick for testing springs with

 

http://www.airsoftspecops.com/Forums/DisplayComments.php?file=Electric Tech/APS_UAR_is_an_Excellent_Spring_Testing_Tool

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