Neck expander mandrels

[thump_rrr]

I load on a Forster Co-Ax and am currently using Redding Bushing Competition Neck Dies on all my precision calibers.

I currently measure the outside diameter of a loaded round and subtract 0.002” for the bushing dimension.
Would there be any advantage to using expander mandrels 0.002” below bullet diameter?
Am I just making more work for myself or will I see a difference on paper?

Also on the K&M website it shows that the Forster Co-Ax press has more limited range than a conventional press when using expander mandrel so more than 1 die will be needed to cover case dimensions from 6mm BR to 338 Lapua.

 

[JFrank]

Can’t hurt to use a mandrel, but certainly ensure .002 under a loaded round is optimum for your combination. At short range it may be difficult to see on paper but I can assure you that a charge ladder at a greater distance the optimum bushing size will be apparent. This is something I do early in the load development process.

 

[thump_rrr]

Thanks.

I have 400y available at the range I typically shoot at.
I may try this out this weekend.

 

[Walkalong]

I like to uniform the ID as much as I can. For me, that means turning necks, or using a bushing that sizes all necks just enough, but that so the expander mandrel does a hair of work on all the necks.

It will be hard to prove on paper, but it makes me feeling good about consistent neck tension, and my loads shoot great, so………

 

[JFrank]

I like to uniform the ID as much as I can. For me, that means turning necks, or using a bushing that sizes all necks just enough, but that so the expander mandrel does a hair of work on all the necks.

It will be hard to prove on paper, but it makes me feeling good about consistent neck tension, and my loads shoot great, so………

Yep
Even if it’s just a clean up trimm, I feel better with turned necks.

 

[Kaldor]

Yep
Even if it’s just a clean up trimm, I feel better with turned necks.

I've often though about getting into neck trimming, but that would take my OCD to a whole new level. I know that even a skim pass does a lot to improve the neck thickness consistency, and neck tension, and I'm a pretty firm believer that consistent neck tension promotes better accuracy. But once again, how much time do I have?

I size with no expander ball, and I do use a mandrel, to set tension at 2 thou. Switching to a mandrel did give a slight accuracy increase, and I feel it works your brass less.

 

[AJC1]

I've often though about getting into neck trimming, but that would take my OCD to a whole new level. I know that even a skim pass does a lot to improve the neck thickness consistency, and neck tension, and I'm a pretty firm believer that consistent neck tension promotes better accuracy. But once again, how much time do I have?

I size with no expander ball, and I do use a mandrel, to set tension at 2 thou. Switching to a mandrel did give a slight accuracy increase, and I feel it works your brass less.

That's how I load, standard die then expander mandrel... works great. Have a 21st century neck turning tool, only played with it a little.

 

[JFrank]

I've often though about getting into neck trimming, but that would take my OCD to a whole new level. I know that even a skim pass does a lot to improve the neck thickness consistency, and neck tension, and I'm a pretty firm believer that consistent neck tension promotes better accuracy. But once again, how much time do I have?

I size with no expander ball, and I do use a mandrel, to set tension at 2 thou. Switching to a mandrel did give a slight accuracy increase, and I feel it works your brass less.

Bart Sauter, arguably the top shooter in the country shoots a no turn neck 6 BRA. He’s done pretty well.

 

[Kaldor]

Bart Sauter, arguably the top shooter in the country shoots a no turn neck 6 BRA. He’s done pretty well.

I know, and that's the issue, or lack of one depending on how you look at it. And it's the primary driver for me to not do it.

I do have some old school Lake City LR brass with the knurling on it that would probably benefit from it as you literally feeling the tension difference case to case when seating, even with annealing. But my Lapua and Peterson brass? Kind of hitting a point of diminishing returns.

 

[Walkalong]

That's how I load, standard die then expander mandrel... works great. Have a 21st century neck turning tool, only played with it a little.

Standard die will over work the necks. If you are going to use a mandrel, I would suggest a bushing die, or a neck honed die.

 

[AJC1]

Standard die will over work the necks. If you are going to use a mandrel, I would suggest a bushing die, or a neck honed die.

I plan to hone my forester when I start competing again. Using range brass I am just playing with speer bullets. When loading burgers or smks I will step it up again. I have a Redding bushing die for the 6br

 

[AJC1]

Bart Sauter, arguably the top shooter in the country shoots a no turn neck 6 BRA. He’s done pretty well.

Makes some good bullets also...

 

[bfalcon00]

I use a 21st century mandrel on my 308 stuff. I absolutely love it set 2 thou under. I do run the brass through my Giraud trimmer every time as well.

 

[Walkalong]

Makes some good bullets also...

I still have some of his bullets from his early days when we shot Benchrest together.

 

[JFrank]

He also said that he doesnt use a mandrel, rather sizes one direction with a bushing die.

 

[JFrank]

I still have some of his bullets from his early days when we shot Benchrest together.

I would be intimidated shooting next to Bart.

 

[jmorris]

Standard die will over work the necks. If you are going to use a mandrel, I would suggest a bushing die, or a neck honed die.

I have seen improvement’s using them instead of the decapping pin expanders. It can be substantial if there is inadequate lube, some expanders can really yank the neck around coming out, where the mandrel style are easier on them.

Probably the best use of a runout gauge, as far as refining ones process, in seeing what works best.

In an ideal situation stuff doesn’t move much though, that generally calls for custom chambers, dies and turned brass, not everyone wants to do that all the time.

 

[murray brook]

Don't be afraid to give a Redding body die along with a Lee Collet die and a good seater die a try. Inexpensive and very straight cartridges are the result. In my testing I found this way as good as a honed die or an expander mandrel. JMO