Changing expander ball for a smaller one

[Swarovski1]

Thoughts please.

I was wondering if I could change the 6.5 expander ball in my 6.5x47 forster die as I believe it's not needed and neck is resized by the die.less stress for the brass as expander ball works it going and back out.put a smaller expander ball for just a guide for the decapping pin.

[justin credible]

You don't need one at all. Wilson dies don't use them and have never failed to decap properly.

[Swarovski1]

Need ball to hold decapping pin in place as far as I know.its probaly threaded.my 284 redding s type die has a smaller thing on it to hold pin on.just wondering what others are doing.

[gun nut]

The exander ball controls the neck tension you get, clean the iside of the necks with a nylon brush before you try to size them and you will find they resize a whole lot easier. You could also polish a thou or 2 off the expander ball to give you a bit more neck tension and reduce the effort that way, but cleaning is best with the mearest hint of lube if needs be.

[Martin52]

........change the 6.5 expander ball in my 6.5x47 forster die as I believe it's not needed..

 

Not needed.....provided you neck turn. Try a Lee Collet die if you don't want to turn. Also, John Whidden sells expander ball sets in increments of 0.001 to get better control and less working of the brass.

 

Martin

[Brillo]

There was a similar thread about neck tension a little while back and it ended up with me changing my neck resizing method.

The post was about using an expander mandrel after sizing the case.

I use a Redding full length sizing die which utilises an expander sleeve rather that the ball thingy on the Forster die. My reasoning at the time was that pulling this sleeve through as part of the sizing operation must be the same as sizing the neck first and then using a mandrel to upsize the neck.

 

The counter argument was that a mandrel gave more consistent neck tension.

 

The only way I could prove or disprove one method was better than the other was to test both. I bought a neck expander mandrel for the calibre in question and then honed it down to the size I needed to give me the neck tension I needed.

I then made up some rounds by sizing the cases with the sleeve (expander ball) in place and the same number of rounds with the expander removed and then upsized the necks with the mandrel.

 

Did I notice a difference between the two sets of test ammo? Not 100 - 200 yards, but my long range groups are much better than before.

I don't know for sure if this is because of using the mandrel method or because my shooting is improving, but I won't go back to the old method.

It might add a bit more time to case preparation but it does allow you to control neck lubrication much better.

[gbal]

Brillo,good to see a data driven approach used....but could you clarify :

 

(no difference in grouping between the two methods at 100/200...)...Ok,got that...

 

"But long range groups are much better than before....." ? do you mean your long range groups with the mandrel ammo are better than your long range groups with the expander ball ammo? (other factors reasonably controlled)

eg a 'same day/few days comparison'-as I take your point about longterm shooting improvement,though as put,it kind of raises some doubts-easily cleared up...there could be alternate advantages of course-so :

 

did they shoot better long range with one method,and which one?

 

gbal

[Brillo]

George, ideally I'd like to spend sometime on the same day at a long range and compare both sets under the same conditions, but I don't have that luxury.

I take your point about other factors, but all I can state is that since using the mandrel ammo my vertical POIs have been much more consistent than with the original expander ball ammo.

 

I can see having re-read my post that I didn't clearly say which method produced the best group, but I hope it alluded to the mandrel groups being the better.

 

One day I hope to do a better data driven test though. But in order to produce a good statistical result worth sharing I'll need at least 30 date points from each set. That'll be a half day's shooting at least.

[gbal]

Thanks,Brillo-that is exactly what I took from your post...mandrel ahead until contradictory data/confirmation.

 

It does take a bit of time,doesn't it;useful to know that 200y isn't the final word,though.....more time!

Add in all the rest (vel/BCs-themselves likely not to be linear and interact.....

 

Heck,doing the ANOVA stats will take all afternoon,and be a lot less enjoyable than collecting the data !

 

atb

g

[Brillo]

Oh yes, colleting the data is the fun bit. It's been a couple or three years since I've carried out an ANOVA or t-test for that matter. I thought I'd left 6-sigma behind when I retired

[Panda]

Interesting comments Brillo. I've been neck turning and neck sizing using L.E. Wilson neck bushing dies since I started long range shooting. However with a new barrel on order I'm going to switch to fl sizing using a decapping pin retainer ball then upsize the neck using under sized mandrels. Hopefully I'll find the same benefit as you have, although I have to admit I'm doing it because I hate neck turning!

[alpha1]

I dont kneck turn but alĺ my neck sizing is done with L.E.Wilson bushing dies. I tried a Lee neck die it was to much of a faff on.

[Martin52]

Need to watch for run out when using an expander mandrel because the case is not supported and the alignment of the mandrel with the case is not assured.

 

A FLS bushing die with and a custom sized expander ball such as made by John Whidden provides case support. Correct selection of bushing size allows case necks to be reduced only sufficient for the expander ball to then lightly skim the inside of the case neck when the ram is lowered.

 

 

Martin