Increasing fps by turning the spring around?

[Hangtight]

Does anyone else have any experience with this? In two different guns I've reversed a non linear spring so the more densely coiled end is inside the piston and seen a 7-10 fps increase. Fit it back the other way and the fps reverts back to what it was.

I'm currently in 'intense discussion' with various people over the effect with them insisting turning the spring around doesn't make a difference, and myself trying to figure out what it is I'm measuring...

So here's my thinking. A non linear spring (M100) weighs 12.6g. This is split about 55:45 one end to the other which means the more densely coiled end is about 1g heavier. This means you have effectively increased the piston weight by 1g by reversing the spring.

From messing around with piston weights, depending on the original  weight and the BB weight, increasing the piston mass by around 1g can give an fps increase of about the same amount as turning the spring around.

Am I kidding myself, or am I heading in the right direction with this?

 

[Prisce]

Or is it that the tightly wound coils hold tension better? So if they are in the piston they deliver said tension quicker, rather than slower when on the spring guide?(longer distance to travel- initial inertia )

 

[Davegolf]

There must be more important things in life??

No one wants to go to bed with that universe anomaly in their head on a sunday evening! Just use a linear spring, tell yourself you never found this, and sleep easy Hangtight x

 

[Hangtight]

The tight would coils are easier to compress, but regardless of what end of the spring they're at the force on then is the same, as is the force acting on the piston.

 

[Hangtight]

Got to occupy my mind somehow during long, boring shifts.

 

[L3wisD]

I once asked @Sitting Duck this question before installing my M100.

This was his response:

Irregular springs -tight coils at one end (and sometimes in middle too)

It is "supposed" to go tighter coils at the back

as this is supposed to help it start retraction easier with looser coils up by nozzle

It will vary slightly if you fit the spring the other way but not a massive amount I have found

If you fit spring the wrong way - tighter coils up towards cylinder head/nozzle you should find the fps increases by about 10fps

I have tried a few irregular cheapo stock springs and this is myfindings in a quick change APS UAR gun - quickest spring change AEG I know

Guarder springs SP100 = a M110

or they rated the Guarder's using 0.25's they say

a guns fps on a 101% M100 or 328fps will vary

longer barrel produces 350 whilst mp5k's produce 300fps

piston bearings/spacers & bearing spring guide/stock guide AOE

All this will effect the final fps results

Hence you can can get 75 fps difference in 2 very very different length guns depending on other factors above that could compress spring more/less

Hence you choose m110 for short guns

& m95 say for L85 510mm barrel or AK47 455mm barrel

as a rough guide only due to creep (all seals being equal/perfect)

soz - waffling

yeah tighter coils to the rear of the gearbox

if it is a bit low you can reverse it to gain about 10fps

hope this helps

Click to shrink...

The oracle has spoken!