Just to add I fitted a delrin spring guide which is sunk into trigger block by about an inch and held in tight with a cross pin , it fits nice and snug in mainspring, I was also going to fit a piston sleeve to the piston but the tolerances are such close fit of standard mainspring left no room whatsoever for even the thinnest PTFE sheet so left it without , as it turned out there is absolutely no twang at all and the gun gun shoots with a satisfying thud !
The trigger is not bad at all once adjusted......not as good as a Weihrauch record unit but I think better than a FWB sport trigger , it’s perfectly good enough for achieving tight groups at 35 to 40 yards as I discovered after a bit of practice .
The cocking effort is a little on the heavy side probably harder because of the short carbine barrel I would imagine it must be a lot easier with a full length barrel ...... but you get used to it and it’s not excessive .