Mandrel vs bushing

[Geno C]

If you're not going to turn necks, would a appropriately sized mandrel get more consistent neck tension than bushings? My thinking is as long as there is enough neck clearance in the chamber as to not interfere, that the id of the neck being uniformed would give a more consistent neck tension than a uniformed od. That is if the necks aren't perfectly uniform in thickness around the entire circumference.

Is my logic flawed?

 

[bsumoba]

Mandrels will give you more consistency, especially with no neck turned brass.

Lots of guys, including myself, now do this.

 

[Webster]

I have a no turn 6BR. Neck clean up only turned to 0.0125". I can slip a bullet into a fired case with my fingers. An inside mandrel pushed into the neck can only make it bigger. Am I missing something?

 

[FeMan]

I agree that unless you turn the necks to get uniform wall thickness on every case, the mandrel is going to give you more uniform neck tension (all other things being equal). You are probably more at risk for higher runout and any donut will be pushed to the outside which could affect clearance and bullet release. If it helps any, I use the mandrels on all my reloading.

 

[chkunz]

I use both, I choose a bushing that gives me a neck ID about 0.001 smaller than I want for final and then get the final ID I want with the mandrill. This way I do the minimum sizing of the neck.

 

[shoot4fun]

Quite a few reload with the Lee Collet die that squeezes the neck around a mandrel. I have begun testing with my 308 ammo to see if it is an advantage. I use my Redding Body Die for FL sizing and then finish with the Collet Die on the neck. Haven't done enough yet to say one way or the other.

 

[Geno C]

I use both, I choose a bushing that gives me a neck ID about 0.001 smaller than I want for final and then get the final ID I want with the mandrill. This way I do the minimum sizing of the neck.

This is what I'm thinking, least amount of working the brass.

 

[Geno C]

I have a no turn 6BR. Neck clean up only turned to 0.0125". I can slip a bullet into a fired case with my fingers. An inside mandrel pushed into the neck can only make it bigger. Am I missing something?

I would be sizing the necks down, either with a fl die or bushing die. Instead of relying on the bushing to give the final id, I would have a specific mandrel, like the ones Whidden sells, to control neck tension.

 

[zipollini]

anneal
tumble in SS media with Dawn and LemiShine
rinse in H20 and baking soda
rinse in 90% isopropyl alcohol and dry
spray outside of case and inside of neck with One Shot lube
FL size with neck bushing
expand neck with Sinclair Gen. II expander with oversize mandrel to set final neck ID
trim, chamfer inside and outside of neck, uniform/clean primer pocket
rinse in 90% isopropyl alcohol to remove One Shot lube and brush inside of neck with nylon brush to remove any chips from inside neck chamfer
Shot 50 rounds of 6XC yesterday. SD=4.6 ES=10

 

[Geno C]

anneal
tumble in SS media with Dawn and LemiShine
rinse in H20 and baking soda
rinse in 90% isopropyl alcohol and dry
spray outside of case and inside of neck with One Shot lube
FL size with neck bushing
expand neck with Sinclair Gen. II expander with oversize mandrel to set final neck ID
trim, chamfer inside and outside of neck, uniform/clean primer pocket
rinse in 90% isopropyl alcohol to remove One Shot lube and brush inside of neck with nylon brush to remove any chips from inside neck chamfer
Shot 50 rounds of 6XC yesterday. SD=4.6 ES=10

Nice sample size. Now can you do that with only the bushing set to the size you're after and do it again? That should be sufficient to give good evidence one way or another.

 

[thefitter]

I use both, I choose a bushing that gives me a neck ID about 0.001 smaller than I want for final and then get the final ID I want with the mandrill. This way I do the minimum sizing of the neck.

Learn something new here everyday.

 

[Dusty Stevens]

Them donuts have gotta be tuff with a sizing mandrel

 

[Geno C]

Them donuts have gotta be tuff with a sizing mandrel

What do you mean?

 

[broncman]

I could be wrong, but full length a set of Redding shell holders to barely bump your brass each time goes a long way to minimizing donuts.
I use a Lee collet and a body die. No issues yet.

 

[snakepit]

I use both, I choose a bushing that gives me a neck ID about 0.001 smaller than I want for final and then get the final ID I want with the mandrill.

Exactly the way I have been doing it the last couple of years and it works great.

 

[searcher]

Dusty is right on the donuts - I use my mandrel to gauge whether I need to turn into the shoulder again. If using bullets that encroach the shoulder/neck junction, the mandrel will help you know you have a problem with the donuts as opposed to simply sizing the necks. When inserting the mandrel, one can really see a big difference between cases which are forming donuts. And I do think you get slightly better results with the uniformity as you mention, though not as much as you might think. That is because even though the inside dimension is more uniform, it does not necessarily correlate to equally uniform neck tension - because your necks are still different thicknesses which create different release points.

 

['Freak]

If so far the neck hasn’t been turned but now a donut has formed, doesn’t this call for at least a skim cut over most of the neck’s length, and as the cut is nearing then getting into shoulder, it’d take out/off the donut?

 

[SWRichmond]

Neck Turned brass
Tumble, etc
Anneal every other time
FL size with bushing die
Trim length if needed / deburr etc
Brush case necks
Expand with mandrel

"Do I really have to do all that stuff?"

Yes.

 

[LRPV]

You guys that are using an expander mandrel as your last step, What are you using for lube and what steps do you take to get rid of the lube before loading?

 

[chkunz]

You guys that are using an expander mandrel as your last step, What are you using for lube and what steps do you take to get rid of the lube before loading?

I do not use lub, have not found it necessary. Since I am minimizing the sizing with the selected bushing there is little working of the brass with the mandrel.