Well, to put it simply, the long barrel is longer than the short barrel.LOL. Seriously., I am not certain what you are asking, but barrel length should be matched to the cartridge IMHO. As an example after extensive testing it was determine that there is no value in a barrel longer than 22 in for a .308 rd. It does nothing to enhance performance after that length. However, in some magnum cartridges like a .338 Lapua etc, a barrel length of 24 to 28 inches is useable to get the best performance. As another example the 5.56 or .223 that is used in Ar's was originally designed for barrels in the 20-24 in length. The original m16 was 20 in.. However with the shortening of the barrels to pistol length, the performance of the 5.56/.223 has suffered and hence the move towards things like the .300 Blackout etc for short range engagements. There is no perfect cartridge for everything ,thou my brother would tell you if you can't do it with a 30-06, you are doing something wrong! Lol!