looks a lot like T05. part # 50 is the spring that is replaced with a ligher spring. it can also be cut 1 1/2 coils but i like the replacement spring idea better. part 51 can also have a coil removed. i tried several different ball point pen springs cut slightly longer than the original(# 50) till i had the right feel. that lightens the trigger pull wt. parts 104 and 105 need to be polished and de-burred so they slide against each other freely. don't bevel the edges, just dull them. the piston rod "mushroom" has a sharp front edge that needs to be de-burred and polished. don't touch the rear edge because that engages the latch plates (104 and 105). a tiny bit of molly rubbed into the interface between 104 and 105 helps. i also polished and molly the bottom straight edge of 102. the trigger screw contacts the bottom edge when you pull the trigger and this can be rough and cause a gritty feel.
![[linked image]](http://www.umarexusa.com/images/PartsDrawings/34-5-N.gif)