Granberg milling chains what I have learned in the past few weeks. I first got them for my Still MS290/MS390 converted, for a 30" bar. I can say I was impressed how good they worked for this little saw. They cut smooth and I believe the half width cutters made it easier for the saw to go through the white oak log I was cutting. I believe a regular chain would have bogged the saw down a lot more.
Now that I have a new 3120xp, I put the 30" bar and Granberg chains on it. First thing I noticed is that I could only give the saw about half the throttle. The saw has so much more power I do not believe the Granberg chain is a good one to run on a 30" bar. The other day I was cutting slabs and went through 3 Granberg chains cutting 12ft oak slabs, I could get about 2 slabs per chain before they were dull. I was wanting to finish the log so I threw a regular chain in it. It was a Sthil Rapid Micro. With that chain I cut through 3 slabs, and it still acted like it wanted more, but I was done with that log. The Sthil chain was twice as fast as the Granberg chain, and used half the fuel.
So when I got home I took the rakers on the Granberg chain down quite a bit more than what it says I should. They now cut much faster than what they did. I can see where the Granberg chain would be useful for a 4ft wide hardwood slab, or a underpowered saw, but I don't believe they are the chain to use for a powerful saw, with a medium length bar. Just my opinion, and I know that don't mean much, but if you have a powerful saw, and a medium length bar, the Granberg chain isn't the one I would buy.