Action Army M140 Progressive Spring

The Action Army M140 Progressive Spring is specially developed for AEG (Electric) airsoft replicas and can serve as an upgrade compared to the standard spring.

We regularly get the question which spring provides which fps / joule which is very difficult to estimate because it is not only dependent on the spring what this value will be after placing the spring. The air seal of the cylinder, piston, piston head and nozzle also have a large share in this.