Post by RBW on May 30, 2008 23:03:25 GMT -5
This thread was the idea of a customer of mine who thought it would be neat to give a complete account of the reseal and tune of his personal 78G.
In this thread I will show the entire process of breaking down and tuning the gun for maximum performance both from a power standpoint and also with shooting ease in mind. The areas I will focus on in this build will be in re sealing it, getting more power from the gun and also modding it to have the adjustable seer which was discontinued on later models.
The adjustable seer along with a lighter trigger spring will not only make the gun easier to shoot, it will also make it more accurate as there will be less effort required to pull the trigger resulting in a steadier aim.
This build will include both the stage-1 and stage-2 mods.
The Stage-1 Mods include:
Modifying the power adjuster pin.
Installing a seer adjustment screw.
Installing a lighter trigger spring.
Re sealing the entire gun (Less the main valve seal which will be done as needed.)
Installing new main spring (Hammer spring)
Shortening the valve cap, Re cutting the O-ring grove, and boring for increased volume.
And streamlining the valve for better flow and to also increase the internal volume of the valve.
Plus any repair work needed to make the gun function correctly, IE broken/missing parts, stripped threads etc.(Costs are Dependant on what repairs are needed)
Stage-2 Mods include the above plus:
Necking the valve shaft for better flow.
Increasing the volume of the valve body by turning it to a larger internal diameter.
Boring out the back of the valve cap for even more volume.
Re cutting, shortening and shimming the transfer pin for clearance. (Must be done when boring out the back of the valve cap.)
Adding a Teflon transfer port and enlarging the valve and barrel ports.
Machining new barrel seat for the Teflon transfer.
I have these mods broken down into two distinct groups that will not only work well together, but can also be built one upon the other. The mods in a stage-1 build will get you good performance without doing the stage-2 mods. The stage-2 mods will give you the ultimate in performance, but some of the stage 2 mods rely on each other and the mods in the stage 1 group to function efficiently, so a stage-1 mod must be done before a stage-2 can be done.
These mods in combination will give you a very tunable gun. With only the turn of the adjuster screw you can go from practice plinking, (for good economy) to full out High Power shooting, (because......Well.......Sometimes you just need to shoot the hell out of something).
Now lets get to it.
In this thread I will show the entire process of breaking down and tuning the gun for maximum performance both from a power standpoint and also with shooting ease in mind. The areas I will focus on in this build will be in re sealing it, getting more power from the gun and also modding it to have the adjustable seer which was discontinued on later models.
The adjustable seer along with a lighter trigger spring will not only make the gun easier to shoot, it will also make it more accurate as there will be less effort required to pull the trigger resulting in a steadier aim.
This build will include both the stage-1 and stage-2 mods.
The Stage-1 Mods include:
Modifying the power adjuster pin.
Installing a seer adjustment screw.
Installing a lighter trigger spring.
Re sealing the entire gun (Less the main valve seal which will be done as needed.)
Installing new main spring (Hammer spring)
Shortening the valve cap, Re cutting the O-ring grove, and boring for increased volume.
And streamlining the valve for better flow and to also increase the internal volume of the valve.
Plus any repair work needed to make the gun function correctly, IE broken/missing parts, stripped threads etc.(Costs are Dependant on what repairs are needed)
Stage-2 Mods include the above plus:
Necking the valve shaft for better flow.
Increasing the volume of the valve body by turning it to a larger internal diameter.
Boring out the back of the valve cap for even more volume.
Re cutting, shortening and shimming the transfer pin for clearance. (Must be done when boring out the back of the valve cap.)
Adding a Teflon transfer port and enlarging the valve and barrel ports.
Machining new barrel seat for the Teflon transfer.
I have these mods broken down into two distinct groups that will not only work well together, but can also be built one upon the other. The mods in a stage-1 build will get you good performance without doing the stage-2 mods. The stage-2 mods will give you the ultimate in performance, but some of the stage 2 mods rely on each other and the mods in the stage 1 group to function efficiently, so a stage-1 mod must be done before a stage-2 can be done.
These mods in combination will give you a very tunable gun. With only the turn of the adjuster screw you can go from practice plinking, (for good economy) to full out High Power shooting, (because......Well.......Sometimes you just need to shoot the hell out of something).
Now lets get to it.