Neck Expanding Mandrel Dies

[rjacobs]

I am looking at getting a tool head setup on my 1050 for processing 5.56 brass.

I am going to obviously trim with a Dillon RT1200, which tends to have very tight neck tolerances and thus requires an expander be run through the brass after trimming.

The trimmer die is a full length die so I dont think I want to run another full length die with expander after the trim die(although I could) so I have been looking at these mandrel expander dies from K&M and Sinclair. Somebody recommended the Lyman M die to do this in station 8, but I dont particularly want to flare the case mouth as I believe that then REQUIRES you to crimp and I dont necessarily want to be forced to crimp.

So any thoughts on running a mandrel neck expander AFTER the dillon full length trim die?

K&M or Sinclair? I am leaning towards the K&M with the window setup.

Any others to look at?

 

[[email protected]]

My K&M expander caused all sorts of run out on my 300 WM, no bueno

 

[Gary Smith]

I would go with the Sinclair, that is what I use before loading up new brass as they are sometimes rather out of round.

 

[gilgamesh1]

I use the M die for pistol and like it for that since it all gets taper crimped in the end. Not something I'd use for rifle as per your reasoning above. I do use the Sinclair and like it well enough, use it mostly for new brass, particularly Lapua. No experience with the K&M. I expand before I trim since the expander rounds the case mouth as GS points out.

 

[Rattler56]

This is what I use. 3/8" Expander Die Body

 

[rocketron]

This is what I use. 3/8" Expander Die Body

this is a pretty good set up. you can get titanium nitride coated mandrels.( $18 each)

the turning mandrels i have measures .001 smaller than bullet dia and the expander is .002 below. 6mm and 6.5mm

 

[rjacobs]

My K&M expander caused all sorts of run out on my 300 WM, no bueno

Good to know. I have read lots of decent stuff about the K&M unit though.

This is what I use. 3/8" Expander Die Body

this is a pretty good set up. you can get titanium nitride coated mandrels.( $18 each)

the turning mandrels i have measures .001 smaller than bullet dia and the expander is .002 below. 6mm and 6.5mm

Good to see that 21st Century has one. Will probably go this direction since I have been super happy with their priming tool. What is the advantage of the titanium nitride coated mandrels? Is it similar to why carbide die's are "better" in that they last longer due to the coating?

 

[former naval person]

K&M works fine for me. Lyman M caused .005 to .009 runout. Lube inside the necks. It helps. I use graphite.

 

[gau17]

I like using the Redding dies with the button sizer. No need to lube and it's free floating.

Redding Carbide Size Button Kit 22 Cal

 

[ksthomas]

rjacobs,

You're taking the long way around the barn here; hone the neck out on the trimmer die. I've used these for years, and they work great, but you're absolutely right; they're too tight as they come from Dillon. The dies are reamed with what appears to be a standard resizing die reamer that is intended for use with an expander ball. I had mine honed out by our machine shop to around .244" or .245" (don't recall which was right for the brass I was using), and that will take care of having to use an expander afterwards. If you're using a wide range of brass (different makes), you'll need to go with the correct measurement for the smallest (thinnest) neck walls of the bunch, so they'll provide sufficient neck tension. This of course means that the thicker case walls may still need the expander mandrel treatment. But you'll still be far ahead in the time saved. Worth thinking about . . ..

 

[Rattler56]

Good to see that 21st Century has one. Will probably go this direction since I have been super happy with their priming tool. What is the advantage of the titanium nitride coated mandrels? Is it similar to why carbide die's are "better" in that they last longer due to the coating?[/QUOTE]

Pretty much, I have loaded thousands of rounds and looks like new with no wear.
I don't use a expander ball, so its another step, however I am not loading for speed and my run out stays around .001 or less.

Also they will custom make them in any size you want.

 

[rjacobs]

rjacobs,

You're taking the long way around the barn here; hone the neck out on the trimmer die. I've used these for years, and they work great, but you're absolutely right; they're too tight as they come from Dillon. The dies are reamed with what appears to be a standard resizing die reamer that is intended for use with an expander ball. I had mine honed out by our machine shop to around .244" or .245" (don't recall which was right for the brass I was using), and that will take care of having to use an expander afterwards. If you're using a wide range of brass (different makes), you'll need to go with the correct measurement for the smallest (thinnest) neck walls of the bunch, so they'll provide sufficient neck tension. This of course means that the thicker case walls may still need the expander mandrel treatment. But you'll still be far ahead in the time saved. Worth thinking about . . ..

Thats an idea, but at some point I think an expander of some type needs to be put through the neck. Ill be using only LC brass.

And not sure I understand what you mean by "still be far ahead in time saved" when running on the 1050 its just another die after the trim station. Wont add any time to the process at all since all the brass has to run through the whole machine anyway.

 

[rjacobs]

Ordered a 1050 tool head, swage backup die setup, 21st century shooting neck expander mandrel(titanium nitride coated) and a dillon .223 trim die.

So the setup will be:
Station 2: Lee universal de-cap
Station 3: swage
Station 6: full length size and trim
Station 8: 21st Century Shooting titanium nitride coated neck expander mandrel

 

[ksthomas]

rjacobs,

The time saved would be in eliminating the need to run that expander mandrel through the cases, though if you're doing this in one of the next stations of a 1050, that eliminates any time advantage there. The other concern here (and what really got my to hone the necks out) is the overworking of the brass by using a die with so tight a neck. Mandrel or expander ball, taking the neck that far down, and then running either of these to establish the final ID of the cases will overwork that material, and lead to cracked necks after a few firings. Just a little something to consider, while you're doing the initial set-up.

 

[Fuzzball]

"Somebody recommended the Lyman M die to do this in station 8, but I dont particularly want to flare the case mouth ..."

So adjust it to do no flaring. ??

 

[rjacobs]

rjacobs,
The other concern here (and what really got my to hone the necks out) is the overworking of the brass by using a die with so tight a neck. Mandrel or expander ball, taking the neck that far down, and then running either of these to establish the final ID of the cases will overwork that material, and lead to cracked necks after a few firings. Just a little something to consider, while you're doing the initial set-up.

Appreciate the advice. I am going to be doing this brass to sell so it will only take one trip through my machine.

Another question for you specifically, if I were to send you my die do you think you could have your machine shop guys hone the neck? I dont know if I have a local shop in St. Louis that I trust to do this correctly. I know there are plenty of machine shops, just dont know if there is one that I trust and our gun smith population is basically non existent. I would be willing obviously to pay you all for it.

 

[rjacobs]

"Somebody recommended the Lyman M die to do this in station 8, but I dont particularly want to flare the case mouth ..."

So adjust it to do no flaring. ??

I didnt realize you could do this until somebody on the Brian Enos website said that is how his is setup. Doesnt necessarily matter as I ordered the setup from 21st Century Shooting.

 

[ZiaHunter]

Ksthomas:

Good suggestion on getting the neck portion of the trimming die honed. I like the 1200 for its speed but rarely use due to the issues you mentioned above in your posts. Think I'll send mine off to the gunsmith.