Jarrett rifles used to have an article a long time ago where he opined there was no need for anything longer than 27". I remember thinking at the time I read it that it made some sense even though there will always be those who disagree. The longest rifle bbl I have is 28. I won't ever build a rifle with anything longer. In fact I kind of doubt I'll have one over 27 inches.
I agree, & disagree
Running something like a 375CT, you need an UBER slow burning powder, which in turn needs an UBER long bbl to burn said powder. Can you run a 26" bbl on that CT? yup, at the expense of needed velocity. Will any caliber be hurt accuracy wise, with a short barrel? Nope, just going to be slower. I run a 30" barrel on my newest LR rig, but it also weighs 16lbs, this is an ambush type of gun not a packer around (I have & it sucks
). I built this rig for accuracy & velocity at all other costs & that's what I ended up with.
I think of it this way: "The more powder I have to burn, the more barrel I'm going to need to efficiently do that." Will it burn? Yup, after the projectile has left the barrel
Makes for cool special effects but doesn't help you any.
In reference to your 308, 22" is fine, 20" would be fine & still get you out quite a ways, stability wise. A 308 can do that because it's a short cartridge with a moderate amout of fairly fast burning powder. I don't believe there is a "one bbl length fits all", too many variables.
Just a little different perspective, over generalizing a VERY broad spectrum
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