current thinking: expander ball vs expander mandrel

[209jones]

I use both expanders and mandrels, and neck and FLS std and bushing dies, I just try to adapt the method to the purpose and see what improvements I can make to the processing and the downrange results. The only guns I still use expanders on are the ones I can't buy other style dies for without buying custom made ones. I use mandrels because I like the way they work compared to pulling over an expander, also ran into a situation, where it improved runout on a bushing die, and they seem to help overall with case neck stretch and provide fine control over neck tension. All the various dies, and the mandrels, just give me options to work with, on the cases I have, the way I want to work them at the time.

 

[Southern shooter 59]

Moving the brass the smallest amount necessary is essential to consistent cases and longer brass life. After much testing, I found that full length sizing with a bushing die and a bushing sized for delivering .002" neck tension then running the case into a LCD for re-centering in case of neck inconsistency produced the least amount of runout in a loaded round. I turn " clean up" the necks after the first firing but with multiple firings there is still some brass flow taking place. They didn't have mandrel dies when I came up with this process. Enjoy the sometimes very frustrating process.
Lawrence Beech

 

[LVLAaron]

Mandrel, all day every day.

 

[William Vogel]

The only problem I see with the expander ball is that it’s pulled back through the neck and puts the case in tension during the process. I believe the whole sizing process should put the case in compression. I have seen the expander ball cause the brass to elongate the case vs simply opening the neck. Remove the expander, size the case and measure before and after. Install the expander and repeat the process. The case will measure longer with the expander. I’ve found that the mandrel being inserted and placing the case in compression doesn’t alter the length.

 

[K22]

The only problem I see with the expander ball is that it’s pulled back through the neck and puts the case in tension during the process. I believe the whole sizing process should put the case in compression. I have seen the expander ball cause the brass to elongate the case vs simply opening the neck. Remove the expander, size the case and measure before and after. Install the expander and repeat the process. The case will measure longer with the expander. I’ve found that the mandrel being inserted and placing the case in compression doesn’t alter the length.

If the inside of the case neck is brushed, the expander ball polished and sized appropriately, the case will not lengthen due to drag on the neck. I have loaded thousands of rounds following the procedure outlined in my post # 6 with no adverse effects on the case.

However, I am not claiming that expander balls are superior to mandrels for precision reloads. I am just saying they can be used without dire consequences for "semi-precision" reload applications.

PS: In my post # 6, I failed to mention the use of a rubber O-ring under the expander ball assemble which greatly aids in keeping the expander ball from pulling the neck off center which also aids in reducing drag. Senior brain omission.

 

[DLT]

The only problem I see with the expander ball is that it’s pulled back through the neck and puts the case in tension during the process. I believe the whole sizing process should put the case in compression. I have seen the expander ball cause the brass to elongate the case vs simply opening the neck. Remove the expander, size the case and measure before and after. Install the expander and repeat the process. The case will measure longer with the expander. I’ve found that the mandrel being inserted and placing the case in compression doesn’t alter the length.

True but it depends on how small the die necks it down. I have some dies I don’t use bc its a fight to pull expander through it even with a lube

 

[209jones]

They didn't have mandrel dies when I came up with this process. Enjoy the sometimes very frustrating process.
Lawrence Beech

Not sure how many years the Lyman 2 step expanders have been around, but, I first used one around 1989 or so, Buffalo Arms had or has custom sized ones that I bought back then, that was what turned me on to using a mandrel, it was far easier, and it just made way more sense to me in using them. I started switching back then.

 

[Kracken McGraw]

I get along with my Forster high mounted expander ball stems in my dies. But on the other hand I’m not trying to beat you guys on here at a match somewhere.

 

[flexible]

thanks for the advice everyone, it's interesting; I've been loading mostly 6mm PPC for the past 18 months and even though i have a mandrel in the T7 turret I've never used it and the expander ball was removed. I started loading 6.5CM years ago and DID use the mandrel. I'm about to start loading the 6.5 again and it will be interesting to see what i need and use.
flexible