I have an old, very early 30-30 Contender rifle barrel, tapered that was rechambered by SSK into a 309JDJ and cut to 15". No break. It has been the most accurate Contender barrel I have.
I shoot 150grn Ballistic Tips and have taken whitetail out to 350 from a shooting blind and rest. I have a TC 2.5x7x28 scope and it has served me through several hundred rounds.
I have other SSK barrels but this is the only rechamber.
Mike

You don't quit playing because you get old, You get old because you quit playing.