Would you use the expander ball?

[RonAKA]

I'm loading up some new 6BR Lapua brass for initial testing in a Savage LRPV. Based on advice from the 6BR site I ordered an expander ball for my Forster Bump Bushing resizing die, to open up the Lapua unprimed brass.

Only measured 11 cases but the neck OD before using the expander ball averaged 0.2672", with a standard deviation of 0.00013". After expansion, average and standard deviation increased respectively to 0.2683" and 0.00016". So, yes they were a little tight.

After loading with Berger 80 grain Varmint bullets, the OD increased to 0.2692". So, it looks like I have about 0.001" of tension. Standard deviation significantly reduced to 0.00007". I'm thinking the bullet has a mandrel effect and reduced the ovality of the neck without a bullet.

So my question would be, whether I should continue to use this expander ball in resizing the fired cases? Have not shot any yet. I plan to use the .267 bushing, so I'm thinking resized cases without the expander should be about 0.268 after springback. So the expander ball may open them up another 0.0003", or essentially very little. Do you see any harm or benefit in doing that?

It seems to me that the ID of the neck is a more critical dimension than the OD. The use of the expander ball would seem to offer a way to make this ID more uniform. The extra working of the brass, compared to bringing it down from .271 or so to .267, would seem trivial.

 

[Kenny474]

On the few die sets I use that have an expander ball, I use it. I haven't really noticed that it hurts anything, though others will have a different opinion for sure.
I use collet dies for most of my reloading for the same reason I use the expander ball, it leaves a consistent and concentric ID. I turn most all my brass and anneal pretty regularly, so any chance of issue with inconsistent neck thickness or hardness is pretty well eliminated.

It's when you have inconsistent thickness or hardness that using an expander ball can push the neck to one side, but I think a bullet will do the same thing when loaded.

 

[UK]

the only reason I would use an expander after firing would be to sort out a dented neck. I run new br brass over the sinclair expander and my figures are very close to yours, on firings 2 and 3 I can use a 269 bushing and still get enough tension to hold the bullet and not be able to push it into the case, on 4 and 5 I use a 268 bushing, planning to anneal after 5 so will not know how it works until then. I hate expander balls as all they ever seem to do is cause concentricity problems with some cases, what really matters is grip from the case neck not tension.

 

[JLDavid]

Try turning your expander ball down a little if you are worried about it effecting neck tension/concentricity. With all my bushing dies, I turn it down so it rounds the case neck on the up stroke, but doesn't expand on the downstroke. With a little experimenting and measuring, you will figure out how much to turn off. I use an ejector so I have a flat spot on almost all my necks before sizing. Before, I always had a little resistance when the case entered the bushing but not any more. With that said, I do not shoot benchrest or any other sport. I load ammunithion for hunting but try to make it as accurate as possible, of course. Just my .02 worth. Good luck.

 

[CJ6]

With bushing style dies I don't use the expander button.

 

[JERRYHM]

Never, Never, Never

Dented case? Push a loaded bullet nose first into the case.
If really bad use a mandrel.

 

[BoydAllen]

Why don't you chronograph it both ways and also check runout on the bullets? If they are just as straight and the ES is smaller (weigh charges) then you have your answer.

 

[Rust]

I've resized with bushing dies with and without the Redding floating carbide expander ball, and with a die with a honed neck with the floating carbide ball. Never noticed any difference over a chrono or one the target.

If the loaded rounds don't show runout, if the neck tension is correct and equal round to round, and if the brass isn't being overworked the method doesn't matter IMO.

I never use brass that the neck has been dented for match loads due to the possibility of uneven work hardening of the neck from being dented until it has been fired and annealed. The dents are ironed out with an expander mandrel. Uniform neck tension is critical in achieving low single digit ES/SD numbers.

 

[Travelor]

I have used both types of dies - those with expander balls and those with changeable collets.

I have found that dies that use the expander balls do so because they under size the necks then use the expander ball pulled through the neck to expand them to a larger size. Again, my opinion - I have found these types of dies to (1) stretch cases; (3) score the inside of the cases; and (3) size the cases unequally causing excessive run out. In other words, they do nothing as well as collet dies.

Collet dies that I use have a insert that holds the cases in alignment with toe collets assuring they are centered on the collet. The collets are changeable allowing the user to use the one for the neck wall thickness that allows for the desired neck tension (I use .001" tension) without stretching, scoring, or causing added run out.

In other words, I find the expander button dies to SUCK compared to collet dies.

Just my opinion, but it is backed by many other shooters and my having a High Master classification in long range F-Class competition.

George

 

[BoydAllen]

The problems that can occur with the use of expander balls result from the amount of expansion that occurs after the neck is sized too much by that portion of the die. If the degree of sizing is such that there is little resistance as the expander is pulled back through the case neck, then there is no problem. You may ask why even use an expander ball? The answer is that with new cases the neck tension may be excessive, and necks may be dented. Also, when shooting unturned necks in a factory chamber, that allows a lot of expansion, cases neck tensions may be more uniform if the neck of the die is honed out so that the expander only moves the brass a thousandth or two, or a bushing selected, for that kind of die, that results in the same thing. I have several concentricity gauges and have measured the results of different methods of sizing.

Travelor,
I believe that what you are calling collets are in fact normally called bushings. http://www.sinclairintl.com/.aspx/pid=40287/Product/Redding_76_Style_Titanium_Nitrate_Bushings____306_to__368

Also, while your observations about the problems associated with ordinary one piece dies that have expander balls are correct, if the problem of excessive sizing of the neck is properly addressed, those problems do not occur, and there may actually be advantages to using a sizing ball, for some applications.

 

[Rust]

Yes, using an expander ball can cause issues when the brass is fired in a sloppy factory chamber, overly sized down by a standard die, with the neck not lubricated enough.

When I start a new project, I acquire a large quantity of brass from a known good lot, make up a couple of dummies to set the freebore length, give Dave Kiff a call to discuss things like the chamber neck diameter (typically .003" over the dummies measurement) and freebore diameter (typically .0004" over bullet diameter) and angle of the leade, and send him the dummies for comparison. This usually results in a one off reamer.

What this accomplishes in minimal expansion and working of the brass which really helps minimize the time spent on each piece. For some chamberings I use a bushing die with or without a floating carbide expander, for others a standard die with a neck honed for minimal sizing with the floating carbide expander. If everything is right, the expander just kisses the brass and can indicate a piece of brass different from the rest.

I've done the thing with tight neck chambers requiring neck turning in the past and moved away from it. In 6.5 X 284, .308 and .223 I've never noticed any difference either across the chrono or on the target.

As previously stated, if the end result is loaded rounds with no runout and equal neck tension, how does it matter how they got that way?