Hi Ridge Runner,
I have a .22-.6mm Remington Ackley reamer with a .252 neck. I had the throat ground away so I can match the customers choice of bullet to the correct throat length with a throating reamer. Throating reamer has a 1 1/2 degree lead angle. With the article in American Rifleman on 1/2 mile .22's recently, I've had several requests for this cartridge.