Girandoni hybrid

[DT Fletcher]

the diagrams on the beeman site are actually very good -

How does the de-cock button / lever work ? I guess it must push the striker latch down out of the way of the hammer tumbler notch to avoid it catching and allow it to pass freely when released ? JB

I have no issues with the diagrams on Beeman's site. My problem is with the words written.

De-cock function: you are correct, the left-side plate lever pushes down the latch so that it will not be hit by the tumbler. This is also how the power can be varied; by pushing the latch down but not completely out of the way of the tumbler. That way the tumbler strikes the latch for less of it's travel. With that, the valve is pushed in a shorter distance which reduces power. (See Arne Hoff, plate 80)

It may be instructive to realize that varying the speed of the hammer (as done with modern airguns to vary power output) on these airguns has the reverse effect. That is, a slower hammer opens the valve slower so a slow hammer actually increases the time the valve is open which increases the output! A very fast hammer opens the valve quickly and reduces the power output.

[Shed tuner]

I have no issues with the diagrams on Beeman's site. My problem is with the words written.

De-cock function: you are correct, the left-side plate lever pushes down the latch so that it will not be hit by the tumbler. This is also how the power can be varied; by pushing the latch down but not completely out of the way of the tumbler. That way the tumbler strikes the latch for less of it's travel. With that, the valve is pushed in a shorter distance which reduces power. (See Arne Hoff, plate 80)

It may be instructive to realize that varying the speed of the hammer (as done with modern airguns to vary power output) on these airguns has the reverse effect. That is, a slower hammer opens the valve slower so a slow hammer actually increases the time the valve is open which increases the output! A very fast hammer opens the valve quickly and reduces the power output.

Thanks, makes sense.