Sorry if I wandered into confusion land Dave.
I had a bar/chain combo (thin kerf, .325 pitch, 18") I got from Bailey's a few years ago. I bought a new rim drum and sprocket to fit that, and also another sprocket for the 20", 3/8", .050 g bar/chain combo.
The stretched chain is 20", 72 d/l, 3/8"-.375". The original Husky chain is also 20", 72 d/l, 3/8"-.375". Those were the ones in the comparison photo.
The new 18" setup is a bit lighter with the Rancher (heavy body), so that helps too.
I now need a file for the thin kerf chain.