recived my special order from russia today , a nice pneumatic spring. thing looks to be quality made from top of the line material the shaft is blued with rich deep finish tube is perfectly finish as well.
my russian freind eaven included a piston seal in the deal .

instalation is prety streight foward . after opening and removing the main spring and guide. and cheking for burs on iside the piston you place the centering plate in the piston. you are ready to close the gun Use spring compressor to do so as the piston is prety stiff , the pre load is not verry long around 3/8 " but it's enough to make that thing powerfull enough.

first impression:

the piston is a great upgreat for that smal sprigner it remove all the twang and lot of the vibration eaven some recoil . i suspect it to be more powerfull but i don't have a crony so i'm in the dark there .