Excellent quality spring made from high performance oil-tempered Japanese SWOC-V steel. This type of steel is generally used in military weaponry and in car engines. The M110 version of this spring was tested in an AEG for over 200,000 shots with only a 0.5% shrinkage in length of which happened in the first 1000 shots which is normal spring shrinkage.
* When choosing an appropriate spring you must match it to the cylinder type and length of the innner barrel. Every AEG is different, use the spring FPS rating only as a rough guide.
* These springs have been rated with no AOE corrected and no trust bearing on the piston head. On some builds I've noticed a 15fps increase just by having a trust bearing on the piston head.
Spring Rating: M120 / 400FPS
Outer Diameter: 14.65mm
Inner Diameter: 11.5mm
Wire Thickness: 1.4mm