Was wondering about performance before I bought my 12.5" barrel. So I researched for days and found there is no real performance benefit for barrel length... just whatever look or use you want out of your rifle. I went for the 12.5" because I want a really accurate, bush friendly gun.
Stumbled on this link when I was doing my research. I believe "Wayupnorth" posted it. You will see performance gains/losses are almost flat in barrel length for the .22
http://www.ballisticsbytheinch.com/22.html
After a quick search I saw this latest thread. It appears that "wayupnorth" doesn't notice much difference.
http://www.canadiangunnutz.com/foru...ith-sporter-and-match-chamber?highlight=Bentz
In doing weeks worth of research the common theme is if you want bench rest competition accuracy then go with target (or even the extreme chamber which is request only at Dlask I believe).
If you want an accurate shooter you can use any ammo and take anywhere then get the sporter chamber.
This is based solely using "google fu" of course.