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Choosing the right spring and making it work.

125K views 91 replies 35 participants last post by  dschmidt 
#1 · (Edited)
NOTE: If your fps is just over your club limit, do not cut the spring. Instead, wrap solder around the piston (If you have the space to do this) and then use a little electrical tape to hold it on. This will slow the piston down and then you should be under your limit. You can remove the solder once the spring has worn in.

To make your FPS more consistent and to give your spring longevity you are best to choose a spring that is bigger than what you need and then cut it down. If done right the spring, once cut, should only just be compressed a little in the cylinder. For example, in my VSR10 I use a Laylax SP190 spring that can produce really massive amounts of energy (way more than I need). I cut a few coils off the spring so that it is only just compressed about 10mm when the gun is not cocked. This means that over the period of time between games the spring does not lose its rigidity.
Also once the spring does start to wear down you can make a little round washer/spacer to fit behind the spring on the guide to put the fps back up a little. With weaker springs you will need to put in a bigger spacer to make a reasonable difference but with stronger springs that have thicker wires, you will only need a little spacer.

Note: When choosing the spring, only get one that is about 50-70fps above your desired rating that you wish for. If you go too big then you will have to cut more coils off the spring and then the spring may fit loosely in your cylinder and may bounce around. Also, before cutting the spring, leave it in your cylinder for 2-3 weeks. This will mean that the initial main loss of energy should have happened and the spring should have stabilized more.

Another interesting note is that manufacturers often test the "M" ratings on springs with a short inner barrel of 220mm x 6.08mm. So if it says "M150" then it is most likely 492fps (150 meters a second)using 0.2gm bb's with a 220mm long inner barrel. Often in your own setup, the fps will be higher as you may have a longer inner barrel

Here is a rough guide for spring ratings once they have worn in.
M90 = 270-285fps
M100 = 300-315fps
M110 = 330-345fps
M120 = 360-375fps
M130 = 390-405fps
M140 = 420-435fps
M150 = 450-465fps
M160 = 480-495fps
M170 = 510-525fps
M180 = 540-555fps
M190 = 570-585fps
Or
SP130 = 445fps
SP140 = 480fps
SP150 = 510fps
SP160 = 545fps
SP170 = 581fps
SP180 = 615fps
SP190 = 650fps
Or
PDI 100% = 290-300fps
PDI 120% = 320-330fps
PDI 140% = 335-345fps
PDI 150% = 350-360fps
PDI 170% = 395-405fps
PDI 210% = 420-430fps
PDI 240% = 450-460fps
PDI 270% = 480-490fps
PDI 300% = 520-530fps

One good thing to note is that Laylax VSR10 springs will also work in a Maruzen/WELL L96 but you may have to drill out the piston a little. Most aftermarket L96 pistons will fit a VSR spring straight off without modification.
Even though Laylax springs cost a little more, I really rate them as they last a lot longer than most other springs.

How to cut a spring
Step 1: Cut the spring with side cutters or hack saw. Normally 1 coil will be about 20fps on a M130 spring. The bigger the spring the more FPS a coil will be. So a M190 spring is normally about 30 fps per coil. (This is only a guideline as not all brands or springs are the same). If you are wanting to take off 2 coils then cut just before 2 coils. So cut about 1 and 3/4 coils.





Step 2:Heat the spring and flatten the pointed part that sticks out.



Step 3:Grind any sharp points



Finished



Also note that spring lengths can effect joule creep.
If a spring has been cut to be the same length as the cylinder, the spring will apply not much force when the piston has reached the end of its travel because the spring will be fully extended. This will mean that the piston will travel fast at the start of its movement but then only gain very little acceleration after the initial burst.
When making a JC rifle, you want the piston to travel slow as the start of its movement and fast at the end. So in this instance, long springs are good.
 
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#3 · (Edited)
good guide !!!!
 
#7 ·
It still feels about as stiff as a normal spring. The main advantage is that the spring will last a lot longer.
 
#10 · (Edited)
The best tip is that with an M130 spring each coil you cut off is about 20fps. It is only a guideline though.
I will try to get it up in the next couple of days. It is pretty simple though.
 
#12 ·
Just edited the part about the L96 springs
 
#13 ·
So I was commenting on this thread: Login

And thought I would share it here too.
I found out that springs has a max compressed length(Lets call it: MCL), and it's not the same as 100% compressed.
So basically, every time this length is exceeded(Even once), the length of the spring is reduced(Maybe only slightly).
And in airsoft this MCL is never(To my knowledge) factored in, resulting in springs getting shorter and weaker.
So that might explain why 1tonne(@ASF) has good results cutting the springs.
As the spring is under little tension, and it might not exceed the MCL.
 
#70 ·
Is this guide right?
Most people are telling me a M150 will be shooting about 520 fps?
M90 = 270-285fps
M100 = 300-315fps
M110 = 330-345fps
M120 = 360-375fps
M130 = 390-405fps
M140 = 420-435fps
M150 = 450-465fps
M160 = 480-495fps
M170 = 510-525fps
M180 = 540-555fps
M190 = 570-585fps
 
#16 · (Edited)
They normally loose about 30fps, maybe 40fps over a the first couple of months but it can depend on the brand of the spring. But all will lose fps over time.
Although, since I cut my springs it has not lost any fps for about 8-9 months since it is not compressed all the time.

New M160 = 520-530fps
Worn in M160 = 480-495fps

Also an M160 will stuff the sears on the stock gun.
 
#17 ·
SP160 spring, is that the one for AEG's? And how do I know it will fit?

(New to upgrading)
 
#18 ·
#19 ·
Ok thank you for the answer. I should have known that.. Any experience with the MAG m190 spring? Want a spring so I can stay close to 540-545fps since the limit is 550.
 
#20 ·
An Mag M190 spring cut down may do the job. You would have to try it.
Don't cut it too short though.
 
#24 ·
#26 ·
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