[PROTEC] Progressive Recoil Spring - P

Progressive Rate Recoil Spring

Uneven pitch recoil spring for gas blowback handguns.

When using with the Marushin FN5-7, please warm up the magazine thoroughly. Compatible models: Tokyo Marui XDM-40, FN5-7 from other manufacturers.

The faster the slide of a gas blowback gun operates, the more efficient and exhilarating it is! The Protec RSP series will make that wish come true.

PROTEC specializes in manufacturing unequal pitch springs for gas blowback handguns. They are a standard custom part for handgun enthusiasts.

A progressive recoil spring (= unequal pitch recoil spring) is a coil spring whose pitch (width) is uneven.

A normal spring (standard recoil spring) has the same pitch (width) from front to back, but a progressive rate spring has both strong and soft sections in one spring.

The slide of a gas blowback gun requires the most energy when it first starts to move, and the opposite is true: when the slide finishes moving backward and moves forward (closing), it requires a strong recoil force.

The current situation is that a standard recoil spring with a constant pitch cannot satisfy these seemingly contradictory requirements.

However, in the case of an uneven-pitch progressive recoil spring, the soft part is compressed the moment the slide starts to move, and then the strong part is compressed after gaining energy (momentum).Then, when the slide moves forward, the set repulsive force of the entire spring closes the slide.

This type of unequal pitch spring mechanism has long been used in motorcycle and automobile suspensions, and some manufacturers also use it in custom springs for electric guns.