Quest for the best neck tension and concentricity.....input please

[mfloski]

First let me say I am pretty new to reloading so give me a bit of a pass if I mess this up!

Second, in the name of searching for the most accurate rounds possible, and a willingness to buy whatever equipment and take the extra time needed, humor me for a minute!

Thinkin through how to achieve the highest levels of neck tension, concentricty...thoughts on the following:

(Omitting some smaller cleaning etc steps)
1. Decap
2. Resize with Redding Bushing die w/expander ball removed
3. Using a Sinclair turning expander die to expand neck
4. Use Hornady or other turning device to turn OD just enough to make concentric and round
5. Using the newly sized neck, determine proper neck tension, and resize neck only with proper bushing to provide one to two thou fit
OR simply use the Sinclair expander die (which is 0.001” bigger than the turning die) and thus open the neck ID to 0.001” fit for bullet

After that process is done the first time, future loading should simply require the use of the proper size bushing and neck sizing, or FLS with bushing if you prefer.

Thoughts?

 

[Threadcutter308]

The only mandrel that will ever go inside of my case necks is that of my neck turner. No expanders of any kind. Neck turning is one of the very first steps I take with new brass. Until you uniform your neck thickness so it is consistent all the way around, you're just wasting your time. You need to know what your chamber's neck diameter is, then determine how much brass to remove from the neck of your cases, to just achieve concentricity. I usually run buttons that are .002" under loaded neck diameter. I chamber with "snug" neck reamers and usually run .002" clearance between the chamber's neck and the loaded round's neck.

 

[mfloski]

So you dont’ worry about the fit between the turning mandrel and case neck ID?

 

[Threadcutter308]

So you dont’ worry about the fit between the turning mandrel and case neck ID?

Actually, you caught me.....good catch. I'm not going to edit/correct my previous post, as the corrected version will only confuse those that have not seen my "mistake".

All of the major neck turning tool manufacturers also sell a Neck "expanding" mandrel, which is intended to size the ID of neck for the turning mandrel/tool. I don't remember for sure, but I think the "expanding mandrel" sizes to 0.001" under the diamter of the neck turning mandrel. And, of course, you do have to reduce the initial neck diameter such that the ID of the case neck is smaller than the OD of the expanding mandrel. I use K&M turners and mandrels and have been very happy with them. Check out their website and also YouTube for their products. Keep doing your research, it isn't black magic and once you get "over the hump" knowledge wise, it'll all fall together. Get out some paper, a pencil and start drawing things out. That will help you understand everything greatly.
Remember to use Imperial sizing lube on the neck turning mandrel. Don' go too fast as the neck turning tool's mandrel will heat up and expand ever so slightly, making neck wall thicknesses from one case to the next inconsistent.