Best way to measure neck wall thickness?

[TheGerman]

For using the Redding Type S dies, having an accurate neck wall thickness is pretty important. Just got done comparing measurements on some brass with different bullets in it, and I am in the ballpark from measurement to measurement, but it varies probably due to the caliper being at an ever so slight angle when closing on the case neck.

What's the best tool out there, or best way to measure case necks on a LOADED cartridge so I can get as close as possible; or is taking 10+ caliper readings the real only way?

Also, just to make sure I'm not missing something. If I take any 223 caliber (.224 diameter) bullet and load it in the exact same case, the diameter of the loaded case neck should be identical regardless of the bullet, right?

 

[Wayne McNeely]

Your best neck wall measurements will be done with an empty case and a tubing micrometer. Measuring with a bullet seated is your next best and should be done with a micrometer so that you can read down to the tenth, that's .0001.

Wayne

 

[Supersubes]

Bullets do vary a bit, but not by much. As far as picking a bushing, that variance doesnt matter since the bushings steps are pretty course. Some bullets show a slight "pressure ring" at the bottom of the bearing surface. Usually it's one or two tenthousanths or so. When I measure necks, I use a blade micrometer(for loaded ammo), and a ball micrometer for direct neck wall measurement.