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thefitter said:Which process provides more consistent and uniform neck tension? A bushing or an expander ball?
thefitter said:This question comes from 2 other threads. Which process provides more consistent and uniform neck tension? A bushing or an expander ball? Thanks
RonAKA said:I think you can have the best of both worlds if you use a bushing die (or honed out FL die) to just size the brass down to slightly smaller than final size, and then pass the expander through last to bring it back up to the final.thefitter said:This question comes from 2 other threads. Which process provides more consistent and uniform neck tension? A bushing or an expander ball? Thanks
RonAKA said:thefitter said:This question comes from 2 other threads. Which process provides more consistent and uniform neck tension? A bushing or an expander ball? Thanks
I would suggest the expander ball gives a more uniform neck tension. The reason is that you are controlling the size of the ID directly. A bushing only sizer can only control outside diameter, and depends on neck brass thickness uniformity to get a uniform ID. If you neck turn your brass, or next best to that, use Lapua brass then neck thickness is probably going to be quite uniform. That said, the ID is still likely to be more uniform with the expander ball.
The knock on the expander ball is that it causes eccentricity of the neck. I think there are two reasons for that. First in a normal sizing die (neck or FL), the neck is sized down to a quite a bit undersized, and then sized back up again quite a bit to the final size. Combine that with a factory chamber that makes the fired brass neck start out quite large, and you have a lot of working of the brass in the neck. It causes it to crack sooner, and also causes eccentricity.
The second reason is the way most dies are made. RCBS, Redding, and others put their expander ball down low in the die so the ball passes through the neck when the case is not well supported. This can pull the neck off centre. Forster puts the expander ball high up in the die so the expander starts into the neck while the neck is still supported in the sizer. This tends to minimize any eccentricity effect.
I think you can have the best of both worlds if you use a bushing die (or honed out FL die) to just size the brass down to slightly smaller than final size, and then pass the expander through last to bring it back up to the final. I use that method and the expander ball only opens the neck up about 0.0003". I feel that is not enough to cause any eccentricity while still making the neck ID uniform.
Not a popular idea, but I use it...
Too bad Lee doesn't make extra mandrels in .001 increments.
That would be the best!
Heavies said:Other than the inability of the Lee collet neck sizer to change/play with neck tension, (without permanently modifying the center mandrel) I feel, this is the best way to get the most consistent tension, and low runout.
The way the die works, IMHO, makes the most sense in consistent sizing and tension.
Due to cheap manufacture, sometimes quality in the machining is lacking. However, in the three calibers that I have used them, they have worked superbly.
Too bad Lee doesn't make extra mandrels in .001 increments.
That would be the best!
Haven't been by in a while, but did you get a chance to read Misfire?