The break came on a old 280 Remington. I no longer own the firearm. Dan Dowling did the work and I'm not sure but he may have made the break. You can see the details in the attached pics. The specs are the threaded minor is .458/459. The OD is .660/661. It is threaded 24 TPI. The bore is .315. $30.00 TYD (conus). PM me, ppal (f&f).