View Full Version : spring installation

08-17-2006, 12:35 AM
I was about to install my new Systema M120s spring, but I'm not sure wether it matters which way I face the spring. If it is an irregular pitch spring, do I need to put it one way or the other ?


Dark Paladin
08-17-2006, 01:38 AM
Moved to appropriate section.

08-17-2006, 03:32 AM
I asked that same question when I got my M120S, but I was told that the direction doesn't matter. AEG should fire the same with either direction.

08-17-2006, 08:25 AM
An irregular pitch spring should have the end with the tighter coils on the spring guide.

08-17-2006, 08:46 AM

08-17-2006, 08:57 AM
That is conventional thinking, but think about it: Does the spring really care which way it goes in? Either way it will be compressed the same set length by the interaction of the sector gear and piston. The location of the coils change in the system, but it doesn't amount to significant change in any variable that has been quantified.

The only reason to keep the tighter coils on the spring guide is to minimize the possibility of the spring binding.

In the grand scheme of things, it doesn't affect how the gun operates enough to worry about until you start getting into very strong springs, i.e. M140 and above. Optimal? No. Will work fine? Yes.

If you have the chance, yes, install the spring with the coils on the spring guide, since it is less likely the spring will bind in that orientation. If you already installed it the other way, don't sweat it.