Originally Posted by fmj
more barrel = better velocity. (more time for pressures to build)
Originally Posted by locutus
Longer barrel= greater velocity.
This is true, the general rule, theory and application, has always been, longer barrel, more muzzle velocity.
But not always, in every case. And certainly not a defining factor when compared to other elements, such as handling and balance, storage, mission/application, etc. Although I always include barrel length -vs- muzzle velocity in the decision making process to one degree or the other.
For example, there is no more difference in muzzle velocity, other than normal chronographed variations, between my Remington M700 26" barrel and my Savage M110 24" barrel, both 308 and both shooting the same ammunition.
Another example is an instructors Remington M700 20" triangle barrel (not really 20", more like 19"), than another instructors Remington M700 police 26" varmint taper barrel.
Typically the general rule is 25 fps muzzle velocity loss with each inch of shorter barrel. But that is a general rule. It could be much higher, it could be much lower. We would all agree, I'm sure, if we took the element of different rifles out of the equation, muzzle velocity loss with a shorter barrel, would be true. However, when comparing different guns (headspace, barrels, etc.) and ammo, it's not a safe bet. And, even when comparing the same gun and barrel, a small loss of barrel length, as say an inch or two, just might not be noticeable by any great degree whether we are making short range or long range shots.
Each barrel, even the heavier varmint taper type as the OP is buying, has a certain amount of harmonic movement. Change the barrel length even a small amount, and that harmonic is changed. It may change for the better, improving accuracy, or it may change for the worse degrading accuracy, or it may not make any apparent difference, but there is a change. This may have something to do with why the accuracy of some rifles have been greatly improved with re-crowning the muzzle, especially if some of the barrel length is removed to also remove damaged muzzle rifling, common with some military surplus rifles.