As far as the saw tune goes. I had to lean it out a whole turn. What does that do to RPMS's and therefore chain speed?
That being still in question I used the same technique I used to do a horizontal bore cut. I had no issues doing them vertically or horizontally. I'm the dork that had a big stump available so decided to practice the cut in a controlled situation with no felling danger before hacking at a tree. Each time I was able to execute the cut smooth as butter with no bucking, no intertial chainbrake testing/verification. Horizontally and vertically.
Things that changed - larger saw, saw not tuned properly, full skip chain full chisel not full comp, longer bar without low profile tip.
Apparently the saw and chain are not the issue, bar and bar size are not the issue.
In my mind that leaves technique and tuning.
I've done it succesfully before but am big enough to say that it could be my technique and I need to get more experience, I will not also rule out tuning as even thought the 372 is pretty powerful- it cut like crap until I got it in tune which leaves me to believe chain speed could have been a factor.
I will be out there this weekend and will make it a point to execute it again the same way and see what the results are and then report back. If not successful I'll try the wiggle method. If still not successful then I will not use that cut until I've tried it with full comp and smaller bar and then go from there.
Safety is very important to me so I always wear full PPE minus a forest jacket with torso protection. I also realize that this cut can be dangerous if your not well versed in the technique, dangers, and precautions to take.
I made sure that when I attempted it my head and majority of my body were out of the line of kickback and had an iron grip on the saw. I will say I was amazed how well the intertia chain brake worked as it barely kicked an inch from the tree before it enguaged. The bar never got more than 2" from the tree with the grip I had on it.
I appreciate all the feedback and this and time everyone has taken to respond and give an honest assesment. I hope this thread helps some others as well as myself.
I will report back next chance I get which may not be until next Sat.