When you think about fast twists versus slow twists in revolver barrels is directly applicable to the same thing in rifle barrels. Standard twist for the 45/70 was/is 1x22. Now the blackpowder guys are shooting 550 grain plain based bullets and going to twists like 1x18 or even faster for the heavier bullets for BPCR shooting. And some of the schutzen shooting done today using the 32-40 cartridge that used a 1x16 twist with 165 grain bullets shooters are also going to faster twists and much heavier bullets. And yes a chronograph is a good addition to any hand loaders tools. I had some 30-06 ammo loaded up with IMR 4320 and kept getting two distinct groups. velocity spread was way over 150 feet per second. Turns out the powder had been made when the production of the IMR powders had been transferred to Canada. Evidently the guys at the IMR plant in the US may have cut some corners to keep the powder in the pipeline. So stopped using the 4320. About 3 months later was checking my powders and when I unscrewed the cap on the 4320 the whole inside of the can was badly rusted. Fertilized the lawn that day. Frank
