Bushing dies that also use expander balls

[mpepin07]

I am looking to get some info on resizing dies which use both an expander ball and a neck bushing. I believe all of the Hornady match grade dies use this set up, I’m sure there are others as well.

In short, my question is does the expander ball negate the effect of the neck bushing?

Here’s my thinking behind this:
The case begins to enter the sizing die and then the neck contacts the expander ball. This will expand the inside of the neck to the same diameter as the ball, with a slight amount of spring-back after passing over it. Then as the case moves further into the die, then neck enters the bushing where the outside of the neck will take the same diameter as the inside of the bushing. As the case then begins to leave the die there is a slight amount of spring-back. Next, the case neck again goes over the expander ball where the inside of the neck will again take the diameter of the expander ball, with spring-back as it completely passes over the expander and is removed from the die. If this is all correct, I don’t see how the neck bushing has any impact on the final diameter of the neck.

Am I thinking about this correctly? If so, why do companies make dies with this setup?

 

[supercorndogs]

Yes and no, the idea is the bushing sizes it too small and the expander ball opens it back up, so as a part of its function it negates what the neck bushing does.

Some people turn necks and run just a just bushing with no expander ball and decapping pin.

The nice thing about using bushing dies with an expander ball, is that you can get a bushing that does not oversize the neck as much as a standard die. I do not know if there is any advantage in practice, but I my perception I prefer it now that I have tried. I probably wont be replacing my standard FL dies for any case I already own.

 

[Supersubes]

I am looking to get some info on resizing dies which use both an expander ball and a neck bushing. I believe all of the Hornady match grade dies use this set up, I’m sure there are others as well.

In short, my question is does the expander ball negate the effect of the neck bushing?

Here’s my thinking behind this:
The case begins to enter the sizing die and then the neck contacts the expander ball. This will expand the inside of the neck to the same diameter as the ball, with a slight amount of spring-back after passing over it. Then as the case moves further into the die, then neck enters the bushing where the outside of the neck will take the same diameter as the inside of the bushing. As the case then begins to leave the die there is a slight amount of spring-back. Next, the case neck again goes over the expander ball where the inside of the neck will again take the diameter of the expander ball, with spring-back as it completely passes over the expander and is removed from the die. If this is all correct, I don’t see how the neck bushing has any impact on the final diameter of the neck.

Am I thinking about this correctly? If so, why do companies make dies with this setup?

With a fired case, the neck doesn’t contact the ball on the way into the die. As supercorndogs said, a bushing can be chosen to minimally size the neck.

Without neck turning, your neck walls vary in thickness. If you just ran the neck into a bushing (no ball) the I.D. of the neck would not be round, as those defects would be pushed to the inside. In the case of a thin neck, you won’t get enough sizing. Both situations create variable neck tension. The expander ball corrects this, and all in one step. You could also use a mandrel, as many do here, to accomplish the same thing.

The problem with expander balls imo has always been their crappy design. Redding is the worst. Long bearing surface, and a whole bunch of threaded connections on a fixed rod. This is pretty much guaranteed to dick up your necks, and require a lot of lube while doing it. The Hornady has a tiny tiny bearing surface, and sits at the end of a floating rod, and suffers none of the problems typically associated with expander balls.

 

[mpepin07]

Thanks for the replies guys. This makes sense to me now.

My question now is I often see people talking about setting neck tension (in thousandths) by changing bushing size. Is it fair to say these guys usually run without expander balls?

 

[spife7980]

Thanks for the replies guys. This makes sense to me now.

My question now is I often see people talking about setting neck tension (in thousandths) by changing bushing size. Is it fair to say these guys usually run without expander balls?

If the bushing is their only mechanism then yes.

 

[mjphawk]

Whidden makes dies with both expander bushings and expander balls. They bushings and expander are available in a variety sizes so you can pick the combination that works for your brass and achieves your desired neck tension. For example a bushing that gives you 0.003” neck tension and am expander that opens it back up slightly to 0.002”.

 

[427Cobra]

I Redding Type S FL dies for all the rifles I load for, and each die has Reddings Carbide Floating Expander Ball, I select a bushing that allows the floating ball to barely touch