K&M Neck Expander

[majohnson]

Anyone using the K&M expanders to correct case neck damage? I keep reading about using expanders that come with die sets are prone to induce neck runout. Does using the K&M have a similar problem?

 

[dkhunt14]

No. I use them all the time. I size with each enough to tension so the expander just Evens them out. I have multiple sizes to control tension. Matt

 

[fa38]

I use them to expand the neck on new brass and any brass I don't have the decapping/expander rod in when I size the brass. Dip the neck in dry lube and make sure there is no crap in your shell holder.

 

[majohnson]

That an interesting idea on using the gaige pins. I made a commitment to reduce my SD and further improve my loads. I notice that my AR case had to much runout. My first step was to return the Reeding dies, they had some damage to the theading on the die body. I went ahead and purchase a set of Whidden FL bushing dies, that made a big improvement in runout.

AR are notoriously hard on brass so I need an expander to take care of the neck damage. It seems like most of what you read about expanders in dies is they induce runout. I don't use any expanders on my bolt gun cases. So using a separate expander before FL sizing should help further reduce my runout.

 

[rardoin]

No. I use them all the time. I size with each enough to tension so the expander just Evens them out. I have multiple sizes to control tension. Matt

I do the same as Matt...excellent runout and neck tension consistency as a result.

 

[majohnson]

Interesting take on K&M.

 

[wholman]

That is a good idea for a die

 

[Pappy42]

JoeR,
Will the collet fit pins of differing sizes within a given caliber?

 

[Fotheringill]

Is this pretty similar to Lee collet neck dies?

 

[mikecr]

I have no issues with bushing downsizing, but also rely on Sinclair's mandrel expansion for reasons Joe describes.
I like his initiative here.

 

[Pappy42]

Thank you JoeR. Does your machinest make these for sale and what is the cost?

 

[Preacher]

Ever time I resize a case in my Warner Tool die I then run it through my K&M expander.
Works for me....

 

[ireload2]

That is a nice set up Joe.
I once used something similar though not nearly as universal or as elegant.
I found a roller burnishing tool with a tapered mandrel that ended with a long .2638 straight section.
I cut out the section of the mandrel that ran from .210 to . 2638 and put it in a RCBS bullet puller using a 6.5mm collet. I connected the bullet puller body to a .44 Mag trim die body with a 7/8-14 nut and installed the lash up in my press. By controlling the depth of the mandrel I could control the diameter. I would normally expand the top of the .222 Mag necks to about .0005 under the bullet dia and the taper of the inside of the neck produced the seating friction so I could fire form the cases to 6X47 Rem. By using a tapered pin you can make it last longer. As it wears just push it deeper into the neck. With a 2 inch long pin you have a lot of length on both ends to use up before replacing a pin.

I decided to get the above die made after my experience with K&M expander and mandrels.

K&M mandrels use a numbering system that is confusing to me and has no relationship to the real world. After a talking to them (is name was Roger I believe) I ordered an expander die and custom mandrel. After receiving the die and mandrel I found the diameter of the mandrel wasn't even close to what I had ordered I contacted them again and asked for a refund. I was told that custom mandrels are individually ground to order and non-refundable. The fact that it didn't measure as ordered didn't faze him a bit. He said depends on the tool one uses to measure. The fact that I use Mitutoyo micrometer didn't matter to him. So, IMO the numbering system and custom moniker it is nothing more than a scam to fleece users out of $27 each for a piece of steel that is nowhere near as precise as a $3 pin gage.

After that experience, I decided to put an end to the expander tower of Babylon. The result is the die you see above. If you want expander mandrel to the 0.001 precision you can get them off Amazon for $3-4 and if you desire 0.0001 precision those are $18 each, and they actually measure that way using a regular micrometer. What a concept.

Kindest regards,

Joe

 

[wolfman]

Joe, I love this solution. I'm curious to hear the steps you take when sizing a case. How do you size the neck down, and by how much before expanding the neck?

 

[wolfman]

Thanks Joe. Makes lots of sense.

 

[LCHDR]

Question for Joe R:
What are you using to put the bevel on the gage pins and get a concentric bevel? Just wondering if it could be done and be good enough with any regular shop tools.
Thanks for the great info on this expander!
LCHDR

 

[jonbearman]

We should get together and do a group buy to get Joe's style expanders made up and then all you need are gage pins and collett's.

 

[LCHDR]

Joe, thanks for all the great info on this!
LCHDR

 

[skiutah02]

We should get together and do a group buy to get Joe's style expanders made up and then all you need are gage pins and collett's.

Im in

 

[Cowtownup]

I like it too...