Air Rifle Spring Cutting Procedure

Cutting the spring is a simple procedure.  Cut the spring by coil count NOT measured length. The 2 half coils at each end of the spring will count as one coil. Use a 4” angle grinder and a thin cut off blade and cut the spring on a sharp angle between the coils. Now the end coil will have to be collapsed so it will sit flat. Heat the coil with a propane flame or MAP gas, you can use an oxy torch if you have one. Only heat a small amount of the spring and just enough that you can squeeze the coil flat with a pair of pliers. Once the coil is squashed flat like the uncut end if the spring let it air cool.  You can then rotate the spring end against a grinding wheel until it is smooth. I generally put this cut end  into the piston with moly lube applied to the end and the piston weight fitted. The compressed solid length of the spring is a critical measurement if the spring is to long it will be solid with the coils touching this will prevent the piston reaching the trigger sear and the piston will not lock back.  The spring will then require cutting some more. The spring solid length can be calculated Wire thickness X Coil count. Most manufacturers have an amount of clearance as the spring should not be compressed over 90% to its solid length.