For you, I'll do one better, I'll explain with a picture.ED-SKaR wrote: That makes no sense whatsoever. Please elaborate.
Ever notice why Airsoft springs come in different lengths? Ever notice a precipitous drop in fps after say, two weeks?
There are two categories of springs. "Hard" springs and "Soft" Springs.
The picture below shows springs from various makers.
In order from top to bottom Hard to Soft springs:
There are 2 clues that the spring you use is a "Hard Spring. One it's shorter and two there is fewer pitch variances.
Hard springs are known as a low variance spring. What you get when you put it in FPS is pretty much what you will get when you check it a month down the line, with a small drop of course. A hard spring loses very little compression length. It stays the same with only a small loss of compression over time.
The problem with a hard spring is that the spring rate is constant over the length of the spring. In the old days (early 2000's) people wanted more speed out of their AEG. Popping in a heavier hard spring resulted in gear box bind ups and piston damage. When the piston was going back the unsupported middle section would bow out and bind up the gear box. The other condition was when the spring was too heavy and the sector gear tried to get a hold of the first tooth of the piston, the force and moment of angle would shear off the back of the piston.
To solve these issues the soft spring were introduces, mainly by SystemA and their Taiwanese Manufacturing counter parts HurricanE. To remedy the spring bowing and piston shearing issues, they introduced a variable spring. They made tighter coils around the middle (as pictured like the two soft springs pictured) and the back. These parts of the spring would start compressing first on initial take up. This reduced piston shear and bowing if installed correctly.
However, if the spring was to have sufficient pop it still had to have the wider coils. Thus the areas with the longer length between pitches, this resulted in a spring that was significantly longer then a hard spring. If you put a bearings on the front and the back. This reduced compression space, so with a long spring and reduced compression space. AEG motors had to work harder to compress the spring. Coils started stacking on top of themselves and that prevented the AEG from cycling properly. This is especially true of SystemA/HurricanE springs that were rated M120+. You should have seen what I was struggling with trying to fit a SystemA 300% spring for a PSG-1 in a dual coil mechbox...duh!
Another disadvantage of a Soft variable pitch spring was that it was made of softer spring steel. This made the spring cheaper and it also reduced "production" costs. These springs would compress and lose its spring rate quickly when put in a mechbox. To account for this eventual compression loss and shrinkage, they over rated their springs. A SystemA spring would lose over 2.5 inches in length. If you bought a M100 SystemA spring, you were sold a spring that would have had a M130 rating fresh from the bag. Then after say 10000 cycles or just sitting in a mechbox compressed for a month. The spring rate would drop down to M100 speed.
I personally do not like Soft springs because of this false-positive. If an AEG was perfect and you put in a Soft spring, you would get a FPS higher than your desired speed range you wouldn't be able to play. This is bad; say a night before an operation with a lower fps limit. Also the compression period varied by each spring. Some would settle after X period of time and some settled after X+5 period of time.
Also the Soft spring would also stress the mechbox more until it compressed down to the lower operating range. We have seen V2 front stress fractures, well put in a M120 Soft spring...that mechbox is experiencing M140 shock impulses...and you know that is not good for a mechbox that is not radius-ed and de-stressed. I personally blew the front end off a TM V2 with a SystemA M100. Cold temps, fresh long soft spring hitting like a M130...buh-bye. It took us awhile back then to figure out what was going on.