case neck won't fit on turning arbor

[ToddKS]

I see you are getting a larger mandrel which may very well solve the problem. If it is still tight, you may need to try passing the mandrel through the case mouth more that one.

I had a batch of Lapua 6.5CM that I had to do that to a couple years ago to turn it.

 

[Mark W]

Sizing the necks seems to be a sensely endeavor as you are making them smaller and then expanding them. I can't see any advantage in this.

It actually makes a lot of sense to size the necks and then expand them in order to get the proper fit on the turning mandrel.

 

[Dusty Stevens]

It actually makes a lot of sense to size the necks and then expand them in order to get the proper fit on the turning mandrel.

This is the way

 

[MGYSGT]

Chuck it up and get some emery cloth. Reduce it until it fits.

 

[rayporter]

you might try expanding and turning immediately after. the longer you wait the more they will try to shrink back to the original size.

 

[NZ_Fclass]

This new brass needs sizing with a FL die before neck turning?

 

[6BRA]

I can't believe some of these answers. LOL

 

[ebb]

Hit one or two with the same tool you use to chamfer the necks when you are loading and see if this helps you start them.

 

[Ccrider]

Be careful of you size before turning. Size all the way down to the shoulder junction and then expand to the shoulder junction.

 

[Webster]

I have a 21st Century neck turner and use a 21st century titanium neck turn arbor (.242) and 21st centrury expander mandrel (.243). I am unable to fit the case neck after FL sizing and expanding onto the neck turning arbor. I have used imperial die wax, HBN, and neolube#2 as lubricants, but the brass will not go onto the arbor. New 6mmBR Lapua brass so no donuts.

What am I doing wrong?

Are the cases fired several times without annealing. Try annealing one with a torch to minimize springback.

 

[209jones]

I forget exactly what size my turning mandrels are, supposedly .002 under caliber, but, I'll expand the neck to .0005 over the turning mandrel with an expander mandrel before turning. I usually hold the case over the sizing mandrel for a few seconds as well, seems to be more consistent on taking to the proper sizing, then leave it that size for the 3 way trimmer as well, and when done, I'll adjust the neck to the size I want to seat at.

 

[Webster]

I have a 21st Century neck turner and use a 21st century titanium neck turn arbor (.242) and 21st centrury expander mandrel (.243). I am unable to fit the case neck after FL sizing and expanding onto the neck turning arbor. I have used imperial die wax, HBN, and neolube#2 as lubricants, but the brass will not go onto the arbor. New 6mmBR Lapua brass so no donuts.

What am I doing wrong?

Simple test for springback. No money spent. Run the expander mandrel into the neck and get a feel for effort to push it in. Repeat a second time and try to get a feel for the difference. There should always be some springback. Take measurements. It may be difficult to measure within 1 thou. I would measure i.d. and o.d. and see if it would help decide which expander mandrel to buy. Don't know what a mandrel cost I would hate to buy an assortment to get the correct one. Good measurements will give the answer. If you FL size before puting the expander in the die it may be reducing the neck a lot under size which means you will have more spring back. The less the expander has to move the brass the less springback you will have. Is a fired case to much over diameter to use an expander? In otherwords you have to close the neck smaller than the expander to make it work. I don't like the idea of sanding the neck turner mandrel, It's made to tight tolerences.

 

[Webster]

Yes, the sizer button was removed.



Pete is sending me a .2430 expander to see if this helps.

Thanks!

My guess is a .243 expander expands to .243 while the expander is in the neck , when the expander is removed it returns to less .243 , the diam. of the bullet. This might be ideal if you want 2 thou tension but the neck turner might not be a good fit. I guess I was lucky everything worked out first try. Don't remember if I sized first with new cases. Have not been to the range in 2 years because of back surgery. Measurements would give you the spring back so you can take a good guess at which expander you need.