As you can see chongo it's all over the map w/the majority going for the shorter barrels. I can tell you anything shorter than 21 is going to have an unpleasant muzzle blast. Shoot for 21 or 22 and it won't be a hindrance in velocity or muzzle blast. powdr
Noise can indeed be a factor.
I'd personally worry more about how the shorter barrel made the rifle balance....
Mine is a full stock Sako L597 with a 20" barrel. It is what it is and a joy to use. If I were to build another, it would be a half stock rifle with a 22".
The longer tube hangs better and is just easier to shoot IMHO.
