Thinking about ditching the expander ball in my FL sizing die and getting a separate expander mandrel die for better/more consistent neck tension. Will this actually help? If so, what does everyone recommend?
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Resizing question
- Thread starter JaredT175
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I do the same for my precision stuff. It’s not a world changer but it will result in better neck consistency. More contact on the sizing surface, for more time.
I like the 21st century body for its simple no frills approach and use a combination of the 21st and sinclair mandrels as they are interchangeable and I got what’s in stock at the time that suited my needs. 21st has some improved surface treatment options as well that should reduce galling chances and sizing friction some, but lube in the case necks is an improvement in feel no matter what treatment you get.
I like the 21st century body for its simple no frills approach and use a combination of the 21st and sinclair mandrels as they are interchangeable and I got what’s in stock at the time that suited my needs. 21st has some improved surface treatment options as well that should reduce galling chances and sizing friction some, but lube in the case necks is an improvement in feel no matter what treatment you get.
I suggest you get a "turning arbor" to start with, you can experiment from there with larger or smaller but its nice middle ground choice.
These used to be for neck turning and so you had the "expander mandrel" which was .001 under bullet diameter to expand all the necks to a consistent diameter and then you ran it over the "turning arbor" which is .002 under bullet diameter as a base for the cutter to press against. That way with the .001 difference in mandrel size there was a few ten thousandths with spring back of space and so it gave you a very consistent cut while still being loose enough to not seize up.
So the turning arbor at .002 below bullet diameter is my recommendation.
If this is for an AR I probably wouldn't bother with the whole endeavor but if you did maybe .003 under would be better so it leaves the neck a hair smaller resulting in a little more bullet grip to keep them from getting beaten up and moving that smidgen more.
What FL sizing die are you using? Is it a bushing die or honed to a specific size? If you try to expand the neck too much with the mandrel you are going to have issues. I try to move mine .001-.002 after sizing with a bushing die.
I have started using the Cortina Precision mandrel dies and even use his Armoloy coated mandrels now. These dies size the base about .0005 more than a standard sizing die will to stop clickers as the base of the case expands. However the reason I like them is that IMO it helps to align the case to the mandrel. I was worried that the case could be slightly off center using a standard mandrel die as there is no case support.
As Spife stated above a mandrel .002 under bullet diameter is the place to start. .264 bullet = .262 mandrel
I have started using the Cortina Precision mandrel dies and even use his Armoloy coated mandrels now. These dies size the base about .0005 more than a standard sizing die will to stop clickers as the base of the case expands. However the reason I like them is that IMO it helps to align the case to the mandrel. I was worried that the case could be slightly off center using a standard mandrel die as there is no case support.
As Spife stated above a mandrel .002 under bullet diameter is the place to start. .264 bullet = .262 mandrel
It is for my 6.5cm bolt gun
I am currently using a Forster standard fl die
Yes I do anneal, actually built my own annealer with an induction heater and a timing relay
You will need to have that die honed to .288 for unturned case necks. It sizes down pretty hard. Measure the outside neck diameter with the expander removed to see how far you would need to expand the neck without honing the die.
I use Forster stander FL sizing dies without the expander ball and had Forster hone them so that the necks are not reduced so much before I run an expander mandrel through the cases to get the neck tension I'm after. To experiment with neck tension I got a set of expander mandrels of different sizes in .0005 increments, which 21st Century Innovation sells.
Doing this works very well for my precision reloading. IMHO, it's not really necessary if one is not really after a lot of precision; where one can get buy just fine using the expander ball or just using bushing sizing dies.
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