Originally Posted by
HuntAway
Would not the increases in velocity have a direct relationship with a fouled bore creating more pressure even with lighter primers?
If you look at the velocities on my target... I think you will see exactly what you are talking about. The barrel was never patched through all of these shots and you can see even with the weaker primers the velocity moves up just a tad. The tighter the bore the better the bore seal increasing pressure and velocity.
In a sealed system the strength of the primer would increase velocity as the primer power was increased would it not. To me that would make sense regardless of vent hole size.
In a flintlock I could see the liner size haveing a direct influence on velocity as gasses are vented through the vent rather than the bore.
I sometimes think of these things while bored at work.
Western has one goal... sell the powder - to do that they need to have reliable ignition across the board - to get that they feel the answer is to increase the size of the flash hole to get more heat to the powder and it makes sense but it certainly is not necessary if the plug can breath correctly.
Ron has shown that the size does not dramtically increase or decrease velocity. If you headspace leaks then you will suffer some loss of velocity. Further if you increase the size of the flash hole you further increase the amount of blow back or back pressure on the nose of the primer this can reduce velocity and if you leak pressure by the the primer the velocity may be further impacted. But in all of this I would think it would be significant.