The main reason I like the plunge cut is that it sets the height of the backcut very accurately.. especially when cutting low near or in the trunk flare, the wood fibers can twist and get all squirly... Not good as the higher the backcut, the greater the distance between the hinge and the more liklihood there will be some imperfection or twist in the wood grain, causing the notch to fail... (Ask me how I know?) Its nice to gun the notch and the backcut in a state of leisure.. One drawback to the plunge is that it does not allow the faller to adjust the gun on the backcut during the fall... and one perk is that it allows the faller to stand away from the stump and call for the pull to break the strap.
The bore cut, or plunge cut with a back release has many purposes.. It is an excellent way to avoid barber chair on heavy front leaners.. That is probably where it gained popularity amongst loggers.. Life and death etc.. I use it for a lot of different reasons
on those bigger diameter trees, my backcut can stray a bit from level... I have a tendancy to cut the back cuts too high, in order to avoid cutting them too low, the fibers in the hinge can get funny with a high backcut, and loss of control results... with the plunge cut, it pretty much doesn't matter how the saw is cutting.. that backcut is right around 1" above the level of trhe notch, right where I like it...
I also like to make the back release cut very low, as I would flush cut the stump... that way the log takes half the stump cut with it... that means less cutting to finish the flush cut and only half a round to handle, which will often go right through the chipper...
Plunge cut allows the faller to pre-set the hinge, getting it just right... Takes a bit of practice though... like anything else... learn in non critical situations and get good before using it when there is a lot at stake..
