Re: 28 3/4" rimfire barrel?
First, my opinion is worth what you paid...now, this is based upon what I have read in the past...
My understanding is that it helps:
Sight radius
More consistent velocity as virtually all the powder is burned inside the barrel, and since 22 bullets are really affected by changes in pressure on the heel as it leaves the barrel, makes the transition from the barrel to the outside world more consistent.
Heavy = steadier (less prone to wobble)
It tends to keep most bullets that are at the speed of sound subsonic for best accuracy as it eliminates both the transonic and supersonic transitions for the bullet....
Again, I am sure there are those on this board that can set me straight where I went awry, but I think I have reasoned well here.