It is interesting that in the two very informative links above it shows that, in the first link using only ball ammo, that velocity went pretty much flat from 20" and longer. Thus, they concluded that a 20" barrel was optimum (with ball ammo).
In the second link with handloads using three different powders the velocity kept increasing right on up to 22", which was the longest length they tested, because that was the length of the barrel they started with.
A 20" barrel on a 223 may be an excellent choice for many people, but saying that length (20") is optimum for velocity, or any other reason, is still a compromise and an over-simplification.
Just about everything is life seems to be some kind of compromise, doesn't it?
Last edited by nifty-two-fifty; 02/24/15.
