Originally Posted by sabotloader

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.



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.