I'm looking for suggestions for the best way to go about floating the barrel in a plastic stock rifle (Win Mod. 70 Super Shadow). Sanding? Grinding? Dremmel tool? It appears that most of the barrel stock contact is on the sides of the barrel. Any suggestions will be greatly appreciated.

I've found what a carbide burr that is called an alumi-cut 1/2" dia in my foredom does the trick. Typical carbide burrs have fine teeth, great for hard metal, not so good for soft stuff. Be aware that material removal is pretty fast, especially if it gets away from you.

I haven't really found anything else that works well, though I'd imagine a good shard scraper should do the trick.

Use a wooden dowel or plastic pipe with some sandpaper glued to it with contact cement. use 220-320 grit, it goes pretty fast. Just find a dowel the size you need, or wrap it with tape or paper (newspaper works good) to get the diameter up to the correct size.