expander buttons -- bad?

[msinc]

Thanks for all of the help. Is there an inexpensive and/or easy to use concentricity gauge that you would recommend?

The one RCBS makes works just fine for me...there are certainly more complicated/expensive ones out there. A little practice and you can get good results with it.
I also have the one Hornady makes. I would not recommend it for checking necks. It is really more to check loaded ammo as it will sit in the chamber.

 

[Ned Ludd]

For the guys that are using the expander mandrels and bushing dies are you using a bushing 0.001 smaller than the mandrel size to ensure the mandrel works the brass correctly?

Yes. The setup I have is Sinclair's Gen II expander die and their "oversized" expander mandrels for .223 and .308, which are ~ .001" under caliber. I generally try to run about .002" neck tension (difference in neck diameter before/after bullet seating). The reason I started doing it this way was that the necks on virgin Lapua brass were all over the map (in terms of diameter) straight out of the box. You could feel a huge difference in resistance when seating bullets for the first firing. When I first started using the oversized expander mandrel, some necks would be opened up significantly, whereas on the the mandrel wouldn't even touch the inside of the neck wall. That made me suspect the "tight" necks out of the box might be very close to .002" neck tension, or even possibly more.

So the idea is to open everything up to a certain minimum size that is larger than the bushing you intend to use. Although I don't usually do it for "important" matches, I have no issues using virgin brass prepaid this this way in F-TR competition. The consistency may not be quite as good as fire formed brass, but it's far better than straight out of the box. I am also not a big fan of simply fire forming brass without getting anything useful in return except fired brass. So I often use prepped virgin brass in local monthly matches. I do not believe the small amount of manipulation "overworks" the necks at all. It's really minimal work as compared to what firing does, and I anneal after every firing. YMMV.

 

[Raythemanroe]

Do you measure your brass? I ask because that bushing isn't doing squat if you are pulling it back out with the expander.. I can't see using an expander, only thing it can do is introduce run out..

Plus you are hitting your brass twice as much.. Brass lasts longer without it..

Ray