Here's a naive question. I hear/read that some cartridges do better with short barrels, some with long barrels. For example, .308 and 7mm-08 are good with a 20" barrel, but you really should have a 26" barrel with a 25-06. Obviously all of them get more velocity out of a longer barrel, but maybe it's diminishing returns for the former examples. I would think all magnums like the slow burning powder, and you want a long barrel. But I also see the 7mm SAUM suggested for a short barrel, and the 300 RCM was built with short barrels in mind. Thoughts?