An update from Kumi Systema Engineering on the release of the Systema PTW Recoil Model. They will be releasing three versions: Training Weapon M4-A1-MAX2 Recoil Model, Professional Challenge Kit  M4-A1-MAX2 Recoil Model, and the Ultimate Challenge Kit  CQBR-MAX2 Recoil Model. Whilst the full release will be delayed, they will be doing a limited release of 100 sets as based on her email:

Since it is very difficult to assemble (assembly of the microswitch device), we had postponed the release, but we have received so many requests, so we prepared the components for the limited 100 sets.

At last, we start accepting the reservation!

Although I think that the number is insufficient, we will estimate in the order of reservation, finalize the order, and we will once stop accepting reservation when reaching to the number.

This limited release is for only 100 sets. Please understand the situation."

See for yourself if you want one in this review by RWTV: