THis thing has soaked up *silly* amounts of abuse. I installed one of these in my RPK before I learned about how important AoE shimming was, and for about two years worth of games, averaging two episodes each where I would dump two drum magazines to support a charge, letting up only to switch, I finally took it apart for maintenance. THe third tooth was a little chewed, and the fourth was just a tiny bit squashed.
THe previous pistons were unable to survive this sort of abuse, being a factory CA reinforced piston and some other polycarb piston I sourced from a pal at a game.
This thing really is incredible.
I have since cleaned up the marring and adjusted angle of engagement with the sector gear, and I anticipate no further appreciable wear in a reasonable timespan.
Lighter than aluminum
Versatile (high speed/high-strain both OK)
G&G's wierdo tolerances (too fat for some shells. High durability makes it a chore to "adjust")
Relatively high cost initially (in the long run, easy to appreciate)
Rating: [5 of 5 Stars!]