Originally Posted by TheyCallMeRambo
m100 springs can be found at homedepot for almost nothing and why need a gundoc is it that hard to swap it yourself?
Thats if you know how to swap it yourself. note that a spring change isn't that simple. since you are going with the M4 series and those cheap ones too, you are probably looking at a v2 gearbox and it needs to be opened up completely to change the spring. also if you are inexperienced with opening it up your spring guide might come flying out the moment u open it up and other parts and whatnot will become loose. hence u need to make sure your gears are shimmed, set properly or you going to have more problems than you can handle in the future.