Mandrel /expander

[patrick021]

i use a neck sizing bushing on my 308 and 338LM I go through my process with my brass but I don't do anything with the inside of my case necks . Is it necessary if so how will it help me with accuracy? Thanks

 

[dok7mm]

If you're not turning your necks, your neck tension can vary due to different case neck thickness, when using the bushings. An easy and fairly inexpensive way to get more equal tension, from case to case, is using an expander mandrel.

I have had good results using a bushing, .003" under caliber to size the neck down, then expanding the neck up .001" using a .002" under caliber mandrel.

Another option is using a FL die with no expander. It will resize your case dimensions and take your neck ID down .003-.004. You can then run a .002" under caliber mandrel to set your neck tension. This is my first choice.

K&M has the die and numerous choices of mandrels and they work fine. I also use a die and mandrels made from pin gauges. Kenny Porter makes this collet type die.

 

[patrick021]

I am using a bushing .002 under , I have never turned my necks ,I have good groups but my es is fairly high will this help?

 

[dok7mm]

It should, but it's like many things, you have to experiment with it, to see if the improvement is worth the extra step. I have found it to be beneficial for me.

 

[Deputy819]

I like the 21st Century mandrels (TiNi) for punching out those necks.

 

[bob4]

Since trying an expander mandrel I have noticed seating feels more consistent.

 

[bigedp51]

i use a neck sizing bushing on my 308 and 338LM I go through my process with my brass but I don't do anything with the inside of my case necks . Is it necessary if so how will it help me with accuracy? Thanks

There is a reason why Redding includes a expander with their bushing dies. That being said the biggest cause of neck runout is if the sizing dies expander is locked down off center.

The advantage of using a expander die is the case neck is expanded on the up stroke of the ram with the case resting on its base.

Tech Line & Tips (FAQs)
Bushing Selection
https://www.redding-reloading.com/tech-line-a-tips-faqs/140-bushing-selection
If the neck wall thickness varies more than 0.002", it may be necessary to use a bushing a couple of thousandths smaller than your calculations indicate, and then use a size button in the die to determine the final inside neck diameter.



I prefer Forster full length benchrest resizing dies with their high mounted floating expanders. This is because they produce the least neck runout of any type die I have ever used.

But now the shocker, a cheap Lee resizing die has the expander centered in its locking collet. And can produce very little neck runout for the average reloader. And the Lee lock ring with its rubber o-ring allows the die to float and self center in the press.

 

[oldfortyfiveauto]

But now the shocker, a cheap Lee resizing die has the expander centered in its locking collet. And can produce very little neck runout for the average reloader. And the Lee lock ring with its rubber o-ring allows the die to float and self center in the press.

Any more Lee dies have become my most used dies.

 

[patrick021]

I'm going to get me the expander mandrel and try it