BerndV
Member
The new carbide mandrels from 21st century are sized 0.0008 smaller than bullet diameter. Does anyone know why they went with this size instead of the standard 0.002 under? I asked them via email but never received a response.
21st Century Carbide Mandrel Question
- Thread starter BerndV
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Rhett Crider
Well-Known Member
Is it a turning or sizing mandrel?
BerndV
Member
Expander mandrel.
Rhett Crider
Well-Known Member
Caliber Specific Expander Mandrel Kits
Our caliber specific expander mandrels are available in .0005” increments in calibers 22 to 338 and will range from .001” above bullet diameter to at least .003” below bullet diameter depending on caliber. This will allow the reloader to find proper neck tension to fine-tune their loads. The...
21stcenturyinnovation.com
You beat me to it; I prefer it because you have more options. For instance, for the OP's query for .264 cal, you only have one option vs. the caliber specific you get .2635", .262", .2615", and .2610."Caliber Specific Expander Mandrel Kits
Our caliber specific expander mandrels are available in .0005” increments in calibers 22 to 338 and will range from .001” above bullet diameter to at least .003” below bullet diameter depending on caliber. This will allow the reloader to find proper neck tension to fine-tune their loads. The...
QuietTexan
Well-Known Member
This specific mandrel is for the neck turning kit; the expander mandrel is larger than the -0.002" turning arbor so that the case neck is expanded large enough to to ride on the turning arbor while being cut. It is not a sizing mandrel used to set case necks.
NCWshooter
Well-Known Member
Could someone simply explain the difference in turning or sizing mandrel as I have never used them at all and I bought some mandrels but I need something else to make them work. LE Wilson is just 10 miles away in Cashmere, WA and I think he has the body or whatever you call it with a slot in it I guess to see what's happening and I need that to get to use the mandrels. Is that right or not? I understand that runout is much less doing this step, but I don't know. I just hunt and target shoot up to 400 yds and have reloaded since 69 but never did these steps nor do I have a chronograph. Any information would be appreciated.
BerndV
Member
No, it is their new carbide expander mandrel. It states that it is an expander mandrel. See the screenshot in post #3:
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It is an expander.
They also offer a turning arbor:
Could be a typo or messed up descriptions. Turning arbors "are sized .002 below bullet diameter."
They also offer a turning arbor:
Could be a typo or messed up descriptions. Turning arbors "are sized .002 below bullet diameter."
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BerndV
Member
An expander mandrel is used to set inside neck diameter on either new or resized brass. It can be done prior to bullet seating or prior to inserting a turning mandrel that is used in conjunction with a neck turning lathe.
QuietTexan
Well-Known Member
Try re-reading, I'll clarify :
This is the black nitride (NOT carbide) expander you put in your post:
Black Nitride Expander Mandrel
21st Century Shooting is excited to unveil a brand new product! Introducing the Slippery black Expanders, this new product will revolutionize the way you reload. Based on our proven technology, these mandrels will reduce friction and galling-they are as hard as carbide and as slick as graphite...
21stcenturyinnovation.com
This is the original stainless steel expander mandrel:
S.S. Expander Mandrel
21st Century Innovation Expander Mandrels when used with our Expander Die Body will expand the case neck for proper fit on the turning arbor. Precision CNC machined from high grade stainless steel. 21st Century Expander Mandrels and Arbors are designed for proper fit in our die bodies. While...
21stcenturyinnovation.com
The original stainless steel expander mandrel is described thusly:
The black nitride mandrel is an updated version of the SS expander mandrel that was specified for use as part of their turning kit. The -0.0008" under caliber spec was chosen to fit on the turning arbor.
They also offer the much more common TiN Expander mandrel:
Titanium Nitride Expander Mandrel
Get them while they last!21st Century Shooting Expander Mandrels when used with our 21st Century Shooting Expander Die Body will expand the case neck for proper fit on the turning arbor. Precision CNC machined from very high grade stainless steel.Our Mandrels and Arbors are engraved: E =...
21stcenturyinnovation.com
The mandrel is NOT carbide, it's steel that has (most likely) undergone a ferritic nitrocarburizing case hardening process.
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QuietTexan
Well-Known Member
"Expander" or "sizing" mandrels generally mean the mandrel expands the case neck to a particular size, usually for use as part of a neck turning kit - they expand case necks to a certain size to ride correctly on the arbor as the case neck is cut. The majority of manufacturers that make mandrels fall into this "for neck turning" category, at least until recently when we've seen a growth in offerings for pre-bullet seating neck expansion.
"Turning" mandrels are a misnomer. They're really arbors in that the work piece (the brass case) is rotating on them, but you still see them listed most places as "turning mandrels". These aren't for sizing - the expanding mandrels are sized to get the brass to fit correctly on the arbor to prevent excessive slop in the cutting process.
21st Century, Porter Tool, K+M, SAC, and a few other companies have branched out into offering very precisely sized sets of mandrels in 0.0005" increments that can be used to very precisely set inner neck diameter before bullet seating. This has been much less common until recently, it's taken off some in the last few years. Used to be most guys used the -0.002" "turning mandrel" or -0.001" expanding mandrel to make the final pre-bullet seating process an upsizing movement in the neck, but we now have significantly more options than repurposed neck turning tools for this.
You need a die body that works with the mandrels you have. Most mandrels with non-threaded heads fit into a Sinclair sized die like this one:
SINCLAIR INTERNATIONAL Products for Sale Online - 237 Products
237 SINCLAIR INTERNATIONAL Products For Sale Up To 91% Off including Reloading, Tools & Cleaning, and Gear.
www.sinclairintl.com
LE Wilson makes "new brass" mandrels that are sized to where they should result in a neck that is 0.0015" smaller than caliber when run through new, unfired brass. This tool is designed to iron out the dings that case necks inevitably get if they aren't shipped in ammo boxes. LE Wilson mandrels are not compatible with Sinclair pattern dies - they tread into a stem which is then treaded into the die body. To use a Wilson mandrel, you need a Wilson die, and vice versa. If you don't have Wilson mandrels, their die won't work for you.
Using mandrels won't automatically reduce runout, but generally using a mandrel to size the ID of the case neck you won't add as much as you otherwise might, especially if you're currently using a button in your sizing die and pulling up through the case neck.
IMO there's no need for you to use mandrels, at the range you said you'll most likely never see a difference unless you're really deep into Benchrest/ F-Class type shooting and are consistently under half-MOA groups already. Not a rabbit hole worth going down unless you're trying to chase smaller groups than you can currently get, and you've already taken care of some other things along the way.
