|
When you are trying for extreme velocity, you will find quite a bit of variation between barrels. I am not saying between brands, but within the same make. Take 5 barrels from brand X and chamber them all the same and fire them across the chronograph. You will likely get quite a bit of variation. The tightness of the bore determines which are fastest, and the barrel makers do not want to get into the business of air gauging barrels to select out the tightest ones. Put moly on a bullet and velocity goes down because that bullet has less resistance as it passes through the barrel, the pressure goes down and the velocity follows the pressure. You have to add to the powder charge to maintain velocity if you use moly; just don't forget to go back if you quit using moly. On extreme velocity I am always hesitant to quote it unless I have seen the chronograph readings myself. I have completed a .22/243 Ackley Imp. for a fellow that is a speed freak and I won't mention his velocity until I see it on the chronograph.
|