Thread: Myth? - shorter barrel = use faster powder?

A faster burning powder for a shorter barrel or is it an old reloaders myth?

So which statement is correct?

Statement 1 - All a longer barrel does is give the powder more time to burn. Burning all the powder gives you all the speed that load can give you. A shorter barrel simply does not always allow all the powder to burn, therefore you should use a faster burning powder in a short barrel to get high velocities.

Statement 2 - The fastest burning powders burn completely within just a few inches down the barrel. The slowest burning powders in a couple of inches more. However, the gas produced by the burned powder continues to expand down the barrel, so a longer barrel will produce higher velocities. Therefore, slower powders that produce the fastest velocities in long barrels also produce the fastest velocities in short barrels.