I cant say I'm terribly offended by the steps in a military barrel. However I was looking for a lathe project and decided to try this.
My plan was to bore each end about .002 small. Put the barrel in the freezer and the sleeve on the wood stove. But I got carried away and was able to push/twist it on. Smeared a little epoxy on it just for good measure.
Once the epoxy sets up I may file/sand a slight roll right where the shroud meets the barrel. I also may not.
The picture says I need to blue the whole thing