I'm into air rifles, nice ones, that's the primary reason I got a lathe. Recently, on one of my air gun forums, someone suggested creating an integral muzzle brake by boring out the muzzle end of the barrel larger than bore diameter. For the project rifle I'm working on, I like this idea. And if it turns out I don't like it in reality, I can always cut off the brake end and turn a brake I do like.

However, that brings up the question of how best to bore the end of the barrel. It was suggested that a piloted reamer would be the way to go, to maintain concentricity with the barrel bore. The concern is, wiping out the rifling with the pilot. Has anyone here tried something like this, and if so, how did you go about it? By all accounts, the steel used in air rifle barrels is quite a bit softer than firearms, so anything with a tool steel pilot will risk destroying the rifling. Is it possible to get a custom reamer made with a brass pilot, or is the pilot just not needed in this case? My intent is a 4-6" brake section, with an actual (rifled) barrel length of around 12", optimum for spring piston air rifles. Any suggestions or ideas would be much appreciated, thanks.

Dave