Crimp effect on Velocity

[Paul Harm]

As I remember shells reloaded a lot of times didn't mean squat - but that could have been a different article. In another article crimp depth effected pressure. Factory depth is around .055 to .060. They said .080 would increase pressure about 1000psi - going less would decrease pressure about the same. In my Accurate powder reloading guide they claim the crimp depth has the greatest effect on pressure seeing how only the shell effects pressure, not the barrel, like a rifle. I've never worried about how many times a shell has been reloaded so long as the crimp depth is still good. One would always have an excuse if he missed - poor crimps. As a side note, man do I love the way my Mec9000H makes a good looking shell. The once fired ones look like factory ammo.