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Expander Mandrels- Mandrel Materials Importance?

spife7980

spife7980

Luchador
Full Member
Minuteman
Feb 10, 2017
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15,430
Central TX
So Im thinking about telling people to get me expanding mandrels for Christmas to get them off my back about gift ideas.

Im pretty sure that the PMA tool looks like the best option, it doesnt look very different from the 21st or Sinclair dies, and looks to be the same in function... unlike K&M which looks proprietary in every way. (I also have an email into porter precision products for their collet die pricing etc)

So with the body being chosen my next choice is the material that the mandrel is made of. Now obviously carbide is the best answer but how much better really? PMA has a carbide mandrel and thats the only ones that advertise carbide expanders, they also have stainless. 21st century has a TiN mandrel and a stainless. Sinclair has stainless. Is the carbide really worth 48 more bucks or a 600%+ upcharge?

I thought that the carbide required zero lube but Ive since learned that lube should still be used with them so that less of a selling point afterall. And since I have to lube them is there really any benefit to using them? I dont imagine that Ill be doing so many thousands upon thousands of rounds annually so as to wear one out. And by that same notion whats the deal with TiN? Just a half way between stainless and carbide?

A year ago I would have jumped at the carbide in a second due to my incorrect notion that carbide expanders were lube free but Ive since learned that only applies to straight wall pistol cases and even then lube wouldnt hurt anything besides tumbling time. If the stainless leave a lubed case the same as a carbide what gives?


PMA expander body- 24.95
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/cdn6.bigcommerce.com\/s-kefrxvu\/products\/105\/images\/291\/DSCN1550__38901.1420222054.500.659.JPG?c=2"}[/IMG2]

PMA Carbide- 56.95
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/cdn6.bigcommerce.com\/s-kefrxvu\/products\/248\/images\/912\/CarbideExpanderWeb__48890.1497548209.500.659.jpg?c=2"}[/IMG2]

PMA stainless- 8.95
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/cdn6.bigcommerce.com\/s-kefrxvu\/products\/99\/images\/285\/PMAExpanderMandrel1__01278.1420222044.500.659.jpg?c=2"}[/IMG2]

21st stainless- 8.95
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/nebula.wsimg.com\/f33e2cf227bb30e42613f591c51399c6?AccessKeyId=D665AA0C95BD1D877538&disposition=0&alloworigin=1"}[/IMG2]

21st TiN- 18.95
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"http:\/\/nebula.wsimg.com\/23ca7462f6f755a97a8be3467653fc1d?AccessKeyId=D665AA0C95BD1D877538&disposition=0&alloworigin=1"}[/IMG2]

Sinclair Stainless- 9.99
[IMG2=JSON]{"data-align":"none","data-size":"full","src":"https:\/\/www.brownells.com\/userdocs\/products\/p_749001145_3.jpg"}[/IMG2]
 
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I've got Sinclair carbide mandrel in 6mm and steel in 22 cal, am upgrading my 22 cal to carbide as well. I notice the difference between the carbide and the steel versions.
 
Crap. I am noticing that the steel is getting really tough to push through. I may pick up the .243 carbide mandrel. Unfortunately, the Sinclair mandrel cost $50 ea.
 
I'm going to caveat my response by saying that my statements are what I believe to be true, but I am always open to learning new things.

That said, I believe that the harder/more lubricious materials like TiN and carbide are going to be more durable/consistent in dimension in the long run. Lube or no lube, we're still talking about a friction interface between your cases and the mandrel(s). Obviously your cases are going to be made of softer materials than would be even the run-of-the-mill stainless mandrels... however, while you only (theoretically) have one mandrel, it will be used with many cases (in other words, to expand 100 cases, each case interfaces with the mandrel once, while the mandrel interfaces with a case 100 separate times). Obviously we aren't talking about the "softer" mandrel(s) failing catastrophically in some manner, but rather wearing over time such that its dimension on Day 1 likely won't be its dimension on Day 1000. I'm no materials engineer and I certainly don't have any practical experience to tell you what the long term wear of expander mandrels looks like, but my intuition tells me that the best bet for long term durability and dimensional consistency will result from using the hardest material you can find for the expander mandrel(s) along with an appropriate mount of appropriate lube.

Sorry I can't be more help.
 
I have both SS & carbide. With lube, I can't tell the difference. Without lube the SS is definately "sticker" in the case neck. But as you have mentioned, if you're going to use lube, for the money the carbide is overrated IMO.
 
I use a Sinclair carbide version as the final step after resizing. I lube the cases before they go through the sizing die but I don’t add any additional before running the mandrel in them. I’ve never used the steel ones so not sure of the difference there.
 
Sheldon N said:
I've got Sinclair carbide mandrel in 6mm and steel in 22 cal, am upgrading my 22 cal to carbide as well.
Click to expand...

Saw that sinclair has turning in carbide but not expanding.

Sheldon N said:
I notice the difference between the carbide and the steel versions.
Click to expand...

How so, and is it any measurable difference via your micrometer or targets?

shotdown said:
Crap. I am noticing that the steel is getting really tough to push through. I may pick up the .243 carbide mandrel. Unfortunately, the Sinclair mandrel cost $50 ea.
Click to expand...

I doubt the wear on them is enough to register on the micrometer but you didnt happen to measure before for a now vs then, would you? It really feels like they are galling up?

Fursniper said:
I have both SS & carbide. With lube, I can't tell the difference. Without lube the SS is definately "sticker" in the case neck. But as you have mentioned, if you're going to use lube, for the money the carbide is overrated IMO.
Click to expand...

See, thats what Im thinking. Ive taken to standing all my brass up on end and purposefully spritzing into the necks as opposed to before where I would just spray while shaking them around and getting enough to not seize in the die. I can no longer tell any difference between the normal and carbide expander balls I got already have. I imagine that the same deal applies to the mandrel but its not exactly apples to apples hence my coming to our brain trust.
 
"A year ago I would have jumped at the carbide in a second due to my incorrect notion that carbide expanders were lube free but Ive since learned that only applies to straight wall pistol cases and even then lube wouldnt hurt anything besides tumbling time. If the stainless leave a lubed case the same as a carbide what gives?"

This statement seems to apply to carbide full length sizer dies (lube not required for straitwall pistol, but is required for carbide bottleneck dies like dillon). Are you sure this is not where you heard this?
 
Where I notice the difference is in sizing effort. I don't lube the inside of case necks, just toss the cases in a bin and give them 2 sprays of alcohol/lanolin on the outside. Very little to no lube makes it to the inside of the case neck. The carbide version sizes smoothly with minimal effort, the steel is a bit more sticky and prone to galling. I see a bit more gunk buildup on the steel mandrel where the carbide one stays cleaner. As far as on target results, measurement or runout, doubt I could see or measure a difference.

I use the turning mandrel as an expander mandrel because it is 0.002 under bullet diameter and that's how much neck tension I'm after. The "expander" mandrel is 0.001 under bullet diameter and that doesn't leave much neck tension.
 
spife7980 said:
Saw that sinclair has turning in carbide but not expanding.
Click to expand...

Are you wanting these to expand for neck turning or a final setting of neck tension? If the latter, the turn mandrel is what you need.
 
MtnCreek said:
This statement seems to apply to carbide full length sizer dies (lube not required for straitwall pistol, but is required for carbide bottleneck dies like dillon). Are you sure this is not where you heard this?
Click to expand...

Not sure I follow your question/meaning? I think that we are on the same page though.

I had at one point read that on the carbide pistol dies that no lube is necessary. I incorrectly took that to mean that lube was not necessary for anything carbide but have since discovered that to be untrue. Bottle necked cases and mandrels still require lube due to the additional friction created when compared to the straight walled cases. I googled the dillon rifle dies and they say that lube is still required so I think thats what you are talking about, if thats so then we are indeed saying the same thing.
 
I have both K&M Carbide and 21st Century TiN. I have discontinued using the K&M Carbide in favor of the TiN. Zero lube and it's smooth as butter. Much tougher, stickier with the carbide and I find it requires lubing the necks. I don't lube necks with the TiN.

you want the turning mandrel for setting neck tension and expander mandrel for turning necks.
 
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Sheldon N said:
I use the turning mandrel as an expander mandrel because it is 0.002 under bullet diameter and that's how much neck tension I'm after. The "expander" mandrel is 0.001 under bullet diameter and that doesn't leave much neck tension.
Click to expand...

MtnCreek said:
Are you wanting these to expand for neck turning or a final setting of neck tension? If the latter, the turn mandrel is what you need.
Click to expand...

padom said:
you want the turning mandrel for setting neck tension and expander mandrel for turning necks.
Click to expand...


For final neck tension. The expanders are .001 under bullet diameter, the turning are .002 under. So with the additional .001" of brass spring back taken into account the expanders would leave the brass necks .002 under and the turning would leave the brass with .003 under. Since we are after .002 normally I would assume that the expander would be what we want. Now if youre after .003 obviously the turning would be the appropriate mandrel.

Where did I go wrong about all of this? It seems like yall are all recommending .003 of tension universally. Well rather it seems like yall are saying that the brass doesnt spring back after the mandrel.
 
I'm not seeing that degree of brass springback, but I'm also annealing every firing and I size to the point where there's only about a half thou of expansion needed anyways. I get .002 final neck tension from my 0.002 mandrel.
 
Sheldon N said:
I'm not seeing that degree of brass springback, but I'm also annealing every firing and I size to the point where there's only about a half thou of expansion needed anyways. I get .002 final neck tension from my 0.002 mandrel.
Click to expand...

I too anneal every firing but thus far only have normal unhoned full length dies so Im opening them up way more at this point. I wonder if thats the difference between .001 and your .0005 spring back? Ive thought about moving to bushing dies but Im not really wanting to make that jump because the 223 that would get the most use is being contemplated for a barrel swap to an AI so Im not sure I want to make that transition thus far. Might get the 6xc forsters honed though, probably should have when I ordered it now in hindsight as this batch of brass should last at least the life of this barrel.
 
bruddah said:
Not sure why you would need to lube a carbide mandrel?
Click to expand...

From what I gathered it still has too much friction and everywhere I read now says it needs some amount of it. But according to those above just stray indirect spray may suffice.
 
spife7980 said:
I too anneal every firing but thus far only have normal unhoned full length dies so Im opening them up way more at this point. I wonder if thats the difference between .001 and your .0005 spring back?
Click to expand...

To clarify, I'm not really seeing springback. Sized cases are 0.002 under loaded cases. The 0.0005 was referring to how much I am expanding the case. Sized cases come out of the honed die with about 0.0025 of neck tension and the mandrel finishes them off. This is measured with calipers so there's probably some springback in there, I'm just not noticing it.
 
Sheldon N said:
I'm not seeing that degree of brass springback, but I'm also annealing every firing and I size to the point where there's only about a half thou of expansion needed anyways. I get .002 final neck tension from my 0.002 mandrel.
Click to expand...

Exactly the same as Sheldon with mine as well. After annealing .002 gives you .002, no springback. It's not the same as when actually firing a case.
 
I am also getting .002 neck tension with the turning mandrel. The expander will only give you .001 tension. I have both in .223, .264, .308 and .002 tension on all 3 with Turning mandrel.
 
Excellent. I’m so glad I made this thread instead of setting my presents up for failure

“We can’t ever do anything right for you” -Family with my gifts but they never accept me telling them to not get me anything
 
I vibratory tumble that leaves carbon in the necks. Carbide expands w/o lube for me. Most of my mandrels are steel and require lube that a vib tumbler won’t remove, so I have to wash those. Real pita.
 
I don't really see the need for lube with the carbide or SS turning mandrel but I tumble with corn media so the carbon is still present. I've found that some bullets & brass like the .001 & some work better with .002. If SS turning mandrel starts to fell a little sticky I wipe it with a scotchbrite pad & it's GTG for quite a while. I don't like to lube because I size with the expander right before loading. I fully prep brass in large quantity & it sits waiting until needed & it will shrink over time from the springback.
I do think the carbide is worth the extra $ & wish they were available in the .262 also.
 
spife7980 said:
(I also have an email into porter precision products for their collet die pricing etc)
Click to expand...


From Porter Precision-
The die body & nut is $85, collets are $25, and pins are $10 each. Collets work on a range of pin sizes but generally you will need a different collet for each caliber that you are working with.

So that’s a bit more but you can get the mandrels in any size you want off of amazon for ultimate flexibility. The cost makes me baulk at it but my desire to tinker still says to get it. I probably won’t
 
I personally cant see a better deal than the 21st Century TiN setup. Die body is $34.99 and the TiN mandrels are $18.95.....
 
I went with PMA carbide mandrels because they are the largest in diameter and give me the closest to .002” neck tension after brass springback.
 
padom said:
I am also getting .002 neck tension with the turning mandrel. The expander will only give you .001 tension. I have both in .223, .264, .308 and .002 tension on all 3 with Turning mandrel.
Click to expand...

What is the diameter of the TiN .30 cal turning mandrel vs expanding mandrel?
 
I did a Google search and found the 21st century die holder at 27.60$ and TiN mandrels are 17.50$ at Bruno Shooters supply.
 
Well I did that with the TiN turning through Brunos, now I get to wait a month to open them...
 
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mojavejim said:
If SS turning mandrel starts to fell a little sticky I wipe it with a scotchbrite pad & it's GTG for quite a while.
Click to expand...

You need to be careful as some Scotch Brite pads have alumina or TiO2 and they will wear SS. The resin Scotch Brite is much less abrasive.

 
With the mandrel chucked up in a drill I use 1200 grit sandpaper to remove the copper off the mandrels, just be attentive.

Doing so polishes up the mandel too. The worst thing that happens is you might get .00005 more neck tension after many tries and remember that the OD of the bullet determines the final expansion so no harm.

 
Anyone know if the TiN 21sr century turning mandrels will fit in a Sinclair expander die body?
 
Concerning this very subject, I'm in the process of trying out a different coating on an expanding mandrel.
 
Afkirby said:
21st century told me that their mandrels are compatible with the Sinclair die body, although I ended up going all 21st century anyway.

-Kirby
Click to expand...

Looking on their website, I don't see any diameters listed for either the turning or expanding mandrels other than the caliber?
 
PMA will also do custom sizes for expander mandrels, though it took them a long a$$ time to do it. I wanted to try more neck tension on my 308 gasser so got one made at .3045" (in SS), seems to have done the trick in my case. That and a Lee FCD crimp closed up my reloads from inches to about .6" at 100..
 
Last edited:
SPAK said:
Anyone know if the TiN 21sr century turning mandrels will fit in a Sinclair expander die body?
Click to expand...

They should

bruddah said:
Looking on their website, I don't see any diameters listed for either the turning or expanding mandrels other than the caliber?
Click to expand...

The expanding mandrel is .01 less than bullet diameter and the turning is .002 less. Ive found this to be true along all manufacturers so far.
 
I called them last week and ordered a 30 and 22 cal expander mandrel. The man said the 30 cal mandrel is .306” plus minus .0001”. The turning mandrel is .001” smaller.
 
I bought a sinclair expander just to compare the sizes to the 21st century and get an empirical measurement for us, Ill update after christmas when I get them side by side. I knew I should have just gotten them for myself and skipped this waiting on santa.
 
^ I picked up a new flyrod for me for Christmas. I had the foresight to pick something that I wouldn't be itching to use right now. ;-D
 
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