My FWB 124, I bough in the 70's , i also at the time bough the Beeman 124 PARTS kit, new piston, factory long spring, cocking shoe & factory piston seal ,when i tryed to shoot after not shooting it for 10 years, I found out about the fac. seal I got my rebuild kit found the sealed bag was like crumbly white wax. Hawaii there is 1 tuner. and had heath issues. luckily I still have the survise book. used lacquer thinner and a dowel with a green scrubby to remove caked on seal & s brass rod to remove marital st edges. Used a drill press chucked the back end of the piston and went from Wet&Dry 3M 220, 320,400,600 to 1500grit. Spring is Air Rifle Headquarters (TWISTER SPRING) must ask not on web site. flatten both ends and polished same as piston. Used aA.R.H. old school button' s @$1.00 each. Used drill press to fit. Used Monguse seal ( put on piston used duct tape tape to protect piston sanded to fit air chamber 150 to 400 grit. polished seal edge with white 0000. polished spring guide to 600. Changed trigger Air Rifle Headquarters ( aluminum ) no longer availble. P. A. has stainless pricey $100+. ( do not do if you are not qualified, I've worked on pistols for 30 years) I cut 1/2 coil on sear spring ,at a time reassembled & tryed. ended up cutting 1 coil. ( tested by bumping on buyt stock from @ 1' must watch MUZZLE I used can stuffed with old t-shirt. After about 300 shots , JSB exact weighed 8.5gr 20 shots A.V. 833fps., deavation (7) fps. Elery Target IMI 7.5gr. low 900's will post more with different pellets later & FWB124 (#2) V-Mach kit results . any one know what is too much power ? FWB #1 is max spacers. This is my 1st attempt. took it apart @ 9 times. also I recommend replacing the cocking arm PIVOT pin. also pretty smooth but more vibration . Used cast BREACH seal ( CANADA) RED COLOR MAY HAVE TO SEND BACK SIDE TO FIT MORE SURFACE AREA BETTER SEAL. I wish I found this blog before I did my 124 would have saved me time.
Thank you and Best Regards
Springer