Looks similar to the tremors kit which destroyed your internals quickly. Looking forwards to seeing how these perform
I mean, the mechanism of operation of the Tremors kit is pretty much identical to that of the TM NextGen M4s, the Bolt Recoil guns and from the looks of things, this G&P Recoil system too.
Essentially, there's a heavy, spring-loaded weight in the stock tube, with a rod that goes into the gearbox casing, and is pushed back by the piston during the last ~20% of the piston's travel.
There are minor differences between all of them, but the principal is identical all throughout.
The Modify Tremors recoil kits only had the reliability issues that they did because the supplied springs for the recoil-weight was too weak/soft, meaning that the recoil weight didn't return quickly enough, causing the piston to engage the recoil-rod while the recoil weight was still moving forwards, which significantly increased the stress on the piston, gears and bearings leading to failure.
The Tremors rifle that I built ended up being reliable for at least
five thousand cycles after fitting a stronger return spring for the recoil weight, but I lost contact with the owner after that.