I recently bought a 221 fireball rifle with a tight neck. I am new to this neck turning.
It has a 248 neck, and my cases measure 253 with a bullet seated in. How much clearance do I need in the chamber for bullet release? In my humble opinion With a bullet seated, the brass OD [outside diameter] should measure .002" to .003" less, [at the pressure ring if the bullet has one]. Just to clarify, some of us turn necks to a specific neck wall thickness, while some of us turn necks so that the Outside Diameter with a bullet seated measures what we're looking. Both methods arrive at the same destination.
What do I need to turn them down to? Turn to an Outside Diameter of .246" to .245". That will give you .001" to .0015" of clearance on each side.
What bushing do I need to get for proper neck tension? I'd have a few on hand that measure .001", .002" to .003" under the OD with a bullet seated. For example, if you use an OD of .246", then bushings measuring .245", .244" and .243" to start.
Sorry if this has been asked before. I am using Lapua 222 brass sized down.
Gabe