I have SIG 3000 Binoculars for sale. Perfect condition, comes with everything as new, plus will add rechargeable batteries and charger.
I ranged targets at close to 5000y.
Perfect for someone who hunts or shoots long/extreme range.
Price $920 shipped.
I saw once, but seems to be more consistent than propane annealing. You need to mess with hot liquid, gloves etc. If this is not a problem for you, than try. I think induction is similar as a result, but much more expensive.