PVP spring specific for use with LiPo 7.4V battery and energy <1J. Given the nature of the platform, the use of energy <1J is directly connected to the use of 7.4V LiPo batteries to avoid hang-ups in the piston stroke with this specific spring. Born from the collaboration between TopMax Elaborazioni (for the dimensional specifications) and Pirani Springs (O.E.M. and technical consultant), the PVP springs (Passo Variabile Progressivo) are made in Italy and are sized and tested using the double bearing on the spring guide and under the piston head on 300.00mm barrels. The TopMax Elaborazioni line of PVP and RCS springs is entirely made by Pirani Springs to our specifications to unite two Made In Italy brands of excellence and quality in the AirSoft sector.


TECH TIP: We recommend inserting the supplied 4.5mm DELRIN shim inside the piston.

The spring is equipped with 3 DELRIN shims of different heights to better manage the energy output at the muzzle.

Technical Specifications of the UMAREX/VFC MP7 AEG gen1/gen2 PVP Spring:

Spring length – 110.00mm,

Outer spring diameter – 14.30mm.

Treatments:
Pre-hardening treatment of steel,

burnishing,

Grinding on the ends (for perfect coplanarity with the guide-spring and bearing surfaces of the piston head,

Progressive variable pitch of the coils,

Product stabilization heat treatment.

We recommend using the spring in the configuration with a bearing on the spring guide and one under the piston head, to obtain the indicated performance and keep the duration as constant as possible over time.