U-all
Lee and I have exchanged a couple of emails and in his last one he has made an interesting point about the 'flash channel'. His concern or thought starts with the ignition of the the primer. With that ignition (explosion) his attention is directed to the 'flash channel' size also. I know in the back of my mind that you could probably 'OPEN' the channel 'TO MUCH' but really was not thinking what his thoughts have suggested - the idea you might open it 'TO MUCH'. His concerns were directed at the efficiency of the primer and it's ability to ignite the powder. As I read and think about his words - This gives more thought to some extent, it may not be the size of the 'flash hole' that gives us the abilty to ignite powder, although it is 'KEY' in the amount 'blow back' pressure that is placed on the primer and the face of the primer block or bolt which ever you have.
Here is part of his explanation - to me his discussion concerns it self with the ability of the primer to do it's job.... From Lemoyne - I am really hoping it is ok to use part of words - because it did start another train of though in my mind...
As I understand it every explosive [which would include priners] has
several characteristics the FPS that it propagates at the force lines of the explosion and the flame temperature. If the force lines of the explosion are properly directed they will carry the pressure and the flame temperature into the powder.
This is not one of my areas of expertise so I am only giving you an
opinion, I am not even sure what type or class of explosive a shot gun
primer falls into. so here is an other opinion, by opening the flame
channel as you suggested we open the confinement allowing the explosive to
burn cleaner and possibly hotter which may help ignition the Lehigh does a
better job of focusing the result into the powder which ends up giving us
better cleaner ignition.
My drawing and my thoughts were on the other end of the spectrum - after ignition.