Originally Posted by kaseyfied
having a longer barrel does matter.. especially when shooting slower powders.. allows more time to burn.. why do u think people use 30-32 barrels? why do u think u get more velocities with these longer barrels??? I am not calling u dumb.. I simple just think your mistaken..
Acutualy thats not quite true. Having a longer barrel simply keeps the bullet exposed to the pressure for longer giving higher velocities but it makes little or no difference to the best burn rate. In terms of best velocity what you are looking for is the flattest curve at max pressureso the bullet gets max pressure for the longest time but as the pressure is rapidly dropping by the time the bullet is 5-6 inches down the barrel it will generally be the slowest powder that will fit enough in the case that gives best velocity regardless of barrel length. Check the reloading manuals, you will find the recommended burn rates in a given cal similar for both pistols and rifle. There are other considerations though such as muzzel blast which can be reduced with a faster powder. If that wasn't the case we could all chop our barrels and just use faster powders .
My favourite 280ai powders with the 160 gr class are Vit n165 and N560