To use, or not to use the expander ball in a Redding bushing die

[Campbell]

Hi all

On a very recent thread someone mentioned that he did not use the expander ball on his Redding bushing die. (I don't want to go off-topic on that thread, so I am posting this)

My natural inclination has been to use the expander ball in order to uniform the neck size by using internal and external forces (opposing forces). (I hope I am making sense?) Whereas only using the bushing is relying solely on external force to resize.

Please will you explain to me the possible benefit(s) of not using the expander ball.

Many thanks

Cam

 

[dmoran]

My input: not in the Redding or any bushing die, do I have a expander ball do any sizing/alteration what so ever.
My why: no extra stretching/sizing/alteration to the case/brass then is needed in the F/L operation.
When I want expansion, I do not want it to occur by pulling back through the neck (pushed through only, in a separate step).

 

[sidecutter]

My input: not in the Redding or any bushing die, do I have a expander ball do any sizing/alteration what so ever.
My why: no extra stretching/sizing/alteration to the case/brass then is needed in the F/L operation.
When I want expansion, I do not want it to occur by pulling back through the neck (pushed through only, in a separate step).

agree agree
throw the expander ball in garbage

 

[Campbell]

agree agree
throw the expander ball in garbage

Many sincere thanks, but please explain why.

 

[Howland]

To those who use the bushing but not the expander ball, are all of you turning necks? If not, how do you maintain consistent neck tension? What velocity SD do you get?

 

[Campbell]

To those who use the bushing but not the expander ball, are all of you turning necks? If not, how do you maintain consistent neck tension? What velocity SD do you get?

Hi Howland

I neck turn to .0135

Cam

 

[Martin52]

Many sincere thanks, but please explain why.

I'll reference a standard 'off the shelf' FLS 0.308 die to help illustrate why - a fired case neck is around 0.342 o/d (depending upon the chamber) , the standard FLS die will reduce this to around 0.328 depending on the die. The expander ball, say 0.306, then works hard to expand the neck back up. So, in this example, the o/d of the neck is reduced from 0.342 to 0.328 then expanded up to 0.306 i/d (~0.335 o/d). That's a lot of work hardening for the brass. When the expander is pulled up and out of the die, it may also pull up the shoulder leading to headspace inconsistency. Lube does help to mitigate this. There are other options - you can choose either a full custom die, made by reference to cases fired from your chamber (eg Whidden), or use a standard die with honed neck (eg Forster). Or, you can use a body die that only sets back the shoulder and then use a Lee Collet die to resize the neck (the LCD squeezes the fired neck down against its mandrel). Lastly, you can size down in a bushing die and use and expander mandrel that inserts and expands the case neck, as opposed to the ball that is pulled out.

If you want to use an expander ball then the standard Whidden FL Bushing die is worth considering. You can select from a range of expander ball sizes to minimise expansion, whilst the correct choice of bushing size will minimise the amount the fired case neck is sized down.

The body die/LCD is a good combination if you are not turning your case necks.

Martin

 

[David247]

I also take the expander ball out, size the cases using a Redding type S full length die and then use a mandrel die to open the neck to the exact size on every case so they all have the same neck tension theoretically. I say theoretically because not all brass is exactly the same even from the best manufacturer and same lot numbers. I turn my necks, anneal every cycle using an AMP unit and seat my my bullets using a hydro arbor press. Then I sort them by seating pressure and there are still some cases that have too much difference in seating pressure than the bulk of them and they get segregated for foulers, etc.

Mandrels are a long cylinder that opens the neck as it goes in and does not allow it to close (spring back) like an expander ball does. As the ball goes down in the neck, the brass can close up a little and as the ball is pulled back up out of the neck, it can pull and stretch the neck. If it is not pulled straight up or if there are differences in neck thickness, the neck can be pulled out of plumb causing concentricity issues. Using a mandrel you have less of a chance of all of that happening. At least that is my understanding of it.

I have also read that people take the expander out and don't expand at all, just relying on the bushing to create the desired neck tension. I don't quite understand this because it seems that turning the necks, using the correct bushing, and then using a mandrel would add a little more assurance that most of your cases would have close to the same seating pressure. It is important to me to get the correct bushing and mandrel so you are not working the brass much at all. These are very fine adjustments. Maybe I go overboard but my SD's are in the single digits and I have very little vertical at long range.

Hope this helps.

 

[Campbell]

I'll reference a standard 'off the shelf' FLS 0.308 die to help illustrate why - a fired case neck is around 0.342 o/d (depending upon the chamber) , the standard FLS die will reduce this to around 0.328 depending on the die. The expander ball, say 0.306, then works hard to expand the neck back up. So, in this example, the o/d of the neck is reduced from 0.342 to 0.328 then expanded up to 0.306 i/d (~0.335 o/d). That's a lot of work hardening for the brass. When the expander is pulled up and out of the die, it may also pull up the shoulder leading to headspace inconsistency. Lube does help to mitigate this. There are other options - you can choose either a full custom die, made by reference to cases fired from your chamber (eg Whidden), or use a standard die with honed neck (eg Forster). Or, you can use a body die that only sets back the shoulder and then use a Lee Collet die to resize the neck (the LCD squeezes the fired neck down against its mandrel). Lastly, you can size down in a bushing die and use and expander mandrel that inserts and expands the case neck, as opposed to the ball that is pulled out.

If you want to use an expander ball then the standard Whidden FL Bushing die is worth considering. You can select from a range of expander ball sizes to minimise expansion, whilst the correct choice of bushing size will minimise the amount the fire case neck is sized down.

The body die/LCD is a good combination if you are not turning your case necks.

Martin

I also take the expander ball out, size the cases using a Redding type S full length die and then use a mandrel die to open the neck to the exact size on every case so they all have the same neck tension theoretically. I say theoretically because not all brass is exactly the same even from the best manufacturer and same lot numbers. I turn my necks, anneal every cycle using an AMP unit and seat my my bullets using a hydro arbor press. Then I sort them by seating pressure and there are still some cases that have too much difference in seating pressure than the bulk of them and they get segregated for foulers, etc.

Mandrels are a long cylinder that opens the neck as it goes in and does not allow it to close (spring back) like an expander ball does. As the ball goes down in the neck, the brass can close up a little and as the ball is pulled back up out of the neck, it can pull and stretch the neck. If it is not pulled straight up or if there are differences in neck thickness, the neck can be pulled out of plumb causing concentricity issues. Using a mandrel you have less of a chance of all of that happening. At least that is my understanding of it.

I have also read that people take the expander out and don't expand at all, just relying on the bushing to create the desired neck tension. I don't quite understand this because it seems that turning the necks, using the correct bushing, and then using a mandrel would add a little more assurance that most of your cases would have close to the same seating pressure. It is important to me to get the correct bushing and mandrel so you are not working the brass much at all. These are very fine adjustments. Maybe I go overboard but my SD's are in the single digits and I have very little vertical at long range.

Hope this helps.

Many thanks

I think I understand your reasoning for not using the expander ball (if my understanding is correct, this is to avoid the pulling of the shoulder caused by the expander ball?).

However, I turn my necks to .0135, and I use a .335 Nitride bushing. Why then do I then need to use a mandrel?

Many sincere thanks for your patience

 

[JFrank]

Many thanks

I think I understand your reasoning for not using the expander ball (if my understanding is correct, this is to avoid the pulling of the shoulder caused by the expander ball?).

However, I turn my necks to .0135, and I use a .335 Nitride bushing. Why then do I then need to use a mandrel?

Many sincere thanks for your patience

There is also the pie crust factor!

The brass necks are being worked from both sides leading to thinning and increased trimming .

 

[Campbell]

There is also the pie crust factor!

The brass necks are being worked from both sides leading to thinning and increased trimming .

Good grief, yep, I understand!

Many thanks, but why does one need to use an expanding mandrel if one uses a specific bushing die?

Cam

 

[JFrank]

Good grief, yep, I understand!

Many thanks, but why does one need to use an expanding mandrel if one uses a specific bushing die?

Cam

Personal choice maybe, I only expand new brass one time to even out any imperfections.

 

[Howland]

.335 - (.0135 x 2) = .308.

What cartridge are you reloading?

If it is a .308 bullet, a standard .306 expander ball won't touch the inside of the neck, nor is anything holding the bullet in the neck.

The example @Martin52 gave above is a perfect example of overworking the neck.

I currently don't have the tools to measure concentricity or turn necks, so I size necks down as little as possible to avoid overworking necks but then use the expander ball to control neck tension (or interference fit).

If I did turn necks, I would be perfectly comfortable using a bushing alone without an expander ball.

 

[Campbell]

.335 - (.0135 x 2) = .308.

What cartridge are you reloading?

If it is a .308 bullet, a standard .306 expander ball won't touch the inside of the neck, nor is anything holding the bullet in the neck.

The example @Martin52 gave above is a perfect example of overworking the neck.

I currently don't have the tools to measure concentricity or turn necks, so I size necks down as little as possible to avoid overworking necks but then use the expander ball to control neck tension (or interference fit).

If I did turn necks, I would be perfectly comfortable using a bushing alone without an expander ball.

Yes, I am reloading .308! Sorry, should have mentioned it before.

I have just removed the expander ball. Since I resize only clean brass using a Lee Universal de-capping die, may I remove the stem from the Redding die without causing any problems?

Sorry for the edit, my new Airedale Terrier puupy wants to fight me!!!


Cam

 

[centershot]

If you remove the expander ball, how you keep the decaping pin from falling out?

 

[JFrank]

The F/L bushing Dies I personally use are designed with a decapper rod only.

 

[Campbell]

If you remove the expander ball, how you keep the decaping pin from falling out?

I don't use it!

I use a Lee Universal de-capping die.

 

[Campbell]

You can take the expander ball off and then replace the piece that was holding it in place so that the decapping pin stays in place. Or you can remove the decapping pin as well and use a dedicated die to remove the primers prior to cleaning.

Many sincere thanks for your clarity

I have now removed the rod that holds the expander-ball/pin assembly.

 

[sidecutter]

Many sincere thanks, but please explain why.

in my opinion the expander ball pulled back through the neck raises
havoc with neck concentricty

 

[DennisH]

Instead of asking individuals questions, I will ask all just one!

Does anybody use the inside neck "Expander Mandrels"?

I do. I also use to turn the inside of the necks, but I don't do it anymore. I don't have the proper equipment to do so. Maybe they have come out with something better lately, if so, I have not seen it.