Problem with Norma brass 243 win.

[340 in Va]

Got time to work on brass, after reading post, (thanks to all that responded) I had to set shoulder back more to get it to work. All brass started at measurement of 1.629, Peterson, Rem., and Federal all worked at 1.6265, the Norma had to be set at 1.624 for it to chamber and bolt to fall on its own. To answer a few other questions: the mandrel is .241 and the necks are 1th larger on Norma brass and I do have the neck turning set-up.

 

[Rflshootr]

Did you happen to measure the neck diameter of a fired case before resizing?

 

[340 in Va]

Did you happen to measure the neck diameter of a fired case before resizing?

Yes, Peterson .2775, Norma .2775, Federal .2765. Still not sure why the Norma brass had to be set back 2th more than the others unless the brass is soft and moves when using mandrel.

 

[340 in Va]

European brass(CIP Specifications) often has a larger web dia than American brass made to SAAMI specifications, and this is the root of your problem, .4701 vs .4713 or larger.

Just because you bump the shoulder back .002, does not guarantee you that the web dimension has been reduced to fit your chamber.

If you have a micrometer, measure the web dimension just in front of the extractor groove of various brands of brass and get ready for a shock.

For giggles and grins, keep running your full length sizer down in very small increments till bolt can be closed easily on the case, then measure the shoulder set back. In some cases, it is necessary to take off .003 from the top of the shell holder on a bench grinder.

I was using Reeding comp. shell holders. Web dia. on Norma and Peterson fired was .4705 and FC was .470, sized Norma .4685, Peterson .469, and FC .4685.

 

[VinceMule]

You figured out your problem!

 

[Rflshootr]

Seat a bullet so that the body of the bullet just goes past the neck/shoulder junction. Measure the neck at the mouth of the case, the center of the neck and at the neck/shoulder junction. Tell me what you see. I'm thinking you'll see some taper in neck thickness. If it's an abrupt change, I'd set up a neck turn to clean up 50% of the neck along it's length. At the base of the neck, it will take more and clean up completely and remove the taper or donut, whichever the case may be. You should only be taking about .0005-.001 off of the diameter at mid-neck. It may not even touch at the mouth of the case.