Theres not much difference in Kerf sizes from using different gauge chains.
Have a look through this "nerdy thread" to see some measured kerf sizes
Today I was using an 880, not mine - one from the milling yard - and it had a 404 chain on it. After using it to cut some fat cookies as bases for placing logs on for milling I noticed the kerf width was not as wide as I remember. So I then got completely distracted by kerf width testing. What...
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To get a significant difference in kerf size you have to go for a different type chain as well as. One if these chains is the "lopro" (low profile) type chain. Its 0.050 gauge but is an odd size pitch. It's sold as 3/8 but its not (neither is real 3/8 chain either) so it requires a special bar and drive sprocket which I have not been able to get.
I made my own drive sprocket by turning down a used 404 sprocket on a lathe, and used a new 0.050, 3/8 tipped bar and kept the chain tight for a the first few logs. If a standard 3/8 drive sprocket is used the chain will continually jump the sprocket but it won't usually jump the nose if kept tight. Eventually the sprocket on the nose wears enough, and the chain stretches enough to ride OK on the bar nose (but not a 3/8 drive sprocket). or logs <18" When starting a new chain on a used nose sprocket its a tad easier than when starting with both new.
I use this type of chain with a raker angle of around 7.5º on a 041 with a 25" bar on my small mil (<18" diam logs) as its much easier to handle on small logs.