That you have not noticed this is a surprise and not much surprises me anymore. My thought is that my durs egg is a beastie and has the flint centered in the pan (which is what we want) and therefore the flint gets the full 'benefit' of the vent blast.
Roger,
Your post caught my attention. The part where your flint is centered in the pan, (WHICH IS WHAT WE WANT).......
It is not so important where the flint ends up pointing, but rather where the sparks hits the priming in the pan. When I work over a lock, having the flint pointing to the center of the pan is not necessarily what I want. I tend to tweak my locks so that the flint is pointing toward the front of the pan, sometimes the very front of the pan so that the flint appears to be pointing off the front of the pan. On most locks this position of the flint tends to produce a shower of sparks to the center of the pan and obviously would cure your problem of rounding the flint from the vent exhaust. I am not sure this would work on every lock that is available, but It has worked for me on the locks I have done. Some locks come made this way and no tweaking is needed.
However, I can imagine a lock maker going to the trouble of designing a lock so that the flint ends up pointing toward the front of the pan and then the purchaser of the lock bending the cock so that the flint points toward the middle of the pan when at rest.
Randy Hedden
www.harddogrifles.com