Mandrels

[Charlie-NY]

I've been using Redding Type S FL dies for virtually all of my reloading. I have no complaints and have produced some very accurate ammo with them. However, in the endless quest to improve my ammo, even by the tiniest bit, I'd like to try using a mandrel to see if improves things.

I "think" I'll need a .262" and .282" mandrel to get started. I have Sinclair mandrels that I used for neck turning (E & T) but I assume that they won't be the sizes that I need. Where should I be getting a good pair of mandrels? Do coatings (TN) matter?

 

[digger11]

Brownells has them all

 

[Ned Ludd]

In terms of springback of the brass, mandrels and bushings have the opposite effect. The neck springs back open slightly after being squeezed down by a bushing, whereas the neck closes up slightly when the mandrel is withdrawn. For this reason, you may want to use a slightly smaller bushing to size down the necks than you would have if the bushing was to be the sole neck sizing step, let's say about .001" or so smaller. This will ensure that the mandrel actually does some work when opening up all of the necks. If the neck ID after the bushing die step is too close to the diameter of the mandrel, the end results will not be as uniform as they could be. So the neck needs to be sized down about .001" smaller than the subsequent mandrel step will leave it.

Next, use a mandrel that is about .0005" smaller than the neck tension/interference fit you're after. For example, if I want .002" neck tension, I'll use a mandrel that is .0015" under bullet diameter. That extra little bit of springback when the neck contracts as the mandrel is withdrawn is worth very close to .0005" in my hands, yielding approximately .002" [total] neck tension. IIRC, neck turning mandrels are typically .002" under bullet diameter, which would generate about .0025" neck tension. 21st Century shooting sells mandrels in .0005" increments:

Expander Die Body

Expander Die Body Introducing the much anticipated Generation X Expander Die Body with viewing window! Set up of an expander die has not been easier! The viewing window allows the user to set the die to allow for optimal mandrel use without “bottoming out”. Machined out of 7075 Aluminum and...

21stcenturyinnovation.com

21st Century Innovation

21stcenturyinnovation.com

 

[dusterdave173]

I got the set from 21st century --they had sale on 4th July--It is nice to have the range- you can use them almost like pin gauges and go-no go to see where you are at any time along the way and their die body with the window makes set up painless I got the std stainless and so far just used some imperial--they seem to be working great with that

 

[swd]

The Porter Tool mandrel die uses gage pins you can order from Amazon for $2-$3 each.

 

[Charlie-NY]

Thanks for the info guys.

 

[nakneker]

I accidentally deleted my post, too long to type again. I’m using 21st century, dies and mandrels though.

 

[6.5 forever]

I've been using Redding Type S FL dies for virtually all of my reloading. I have no complaints and have produced some very accurate ammo with them. However, in the endless quest to improve my ammo, even by the tiniest bit, I'd like to try using a mandrel to see if improves things.

I "think" I'll need a .262" and .282" mandrel to get started. I have Sinclair mandrels that I used for neck turning (E & T) but I assume that they won't be the sizes that I need. Where should I be getting a good pair of mandrels? Do coatings (TN) matter?

I have a carbide 6.5 mandrel that is very smooth. I also have a 7 mandrel that is stainless and it gets a ton of build up. And it drags.

 

[Geronimo Jim]

Always use the same mandrel mfg as turner.

 

[RabbitSlayer]

21st century with the window. They dont make 17 or 20 cal. I got those at brownells. They work in the 21st die body.

 

[Benchrest Braxton]

If you want 2 thou under, go with the black nitride 21st century turning mandrels, they are awesome

 

[David Christian]

I've been using Redding Type S FL dies for virtually all of my reloading. I have no complaints and have produced some very accurate ammo with them. However, in the endless quest to improve my ammo, even by the tiniest bit, I'd like to try using a mandrel to see if improves things.

I "think" I'll need a .262" and .282" mandrel to get started. I have Sinclair mandrels that I used for neck turning (E & T) but I assume that they won't be the sizes that I need. Where should I be getting a good pair of mandrels? Do coatings (TN) matter?

@Charlie-NY , @Ned Ludd gave you a great overview of the mechanics of sizing. When I think about sizing brass, I consider a few critical items.

1. Is my brass annealed in a consistent way?
2. Am I sizing the brass enough to move it beyond its yield point so that the size sticks?
3. Am I using a mandrel size that expands the necks back out beyond its yield point again?

In my experience the brass needs to move at least .002 each way to move beyond ‘yield” each way.

Hope this helps.

Added: yes, TN coated are better than pure stainless, carbide are the best as suggested by @6.5 forever above.

 

[MarkTrew]

Using Porter’s mandrels really allows the individual to fine tune the size. The spring back does change depending on the amount of firings since the last annealing.
MarkTrew

Mandrel Dies – Porter's Precision Products

www.portersprecisionproducts.com

 

[Dimner]

I was wondering about this. Why is TN, black nitride, and carbide better for neck expanding? I understand the need for carbide for cutting tools, but brass over stainless steel seems to be enough right? I guess unless you are expanding a very large amount.

I only have ever used stainless steel and the expander plugs are just as nice as the day I bought them.

 

[RabbitSlayer]

I was wondering about this. Why is TN, black nitride, and carbide better for neck expanding? I understand the need for carbide for cutting tools, but brass over stainless steel seems to be enough right? I guess unless you are expanding a very large amount.

I only have ever used stainless steel and the expander plugs are just as nice as the day I bought them.

Im not positive, but my stainless and coated both collect brass and I still lube both mandrels. Im just not as anal about it. I was using imperial wax but now dry lube.

 

[Charlie-NY]

Is it necessary to use lube when using TN or carbide mandrels?

 

[ksnyder]

I can’t remember who makes them but I have some that are football shaped and like them a lot better the the straight ones

 

[Chris Edmondson]

If it's in the budget, get yourself a good 0.0001" micrometer. Gage pins are sold as +/- which is a tolerance, mandrels in the reloading trade aren't as specific. With a sub-tolerance or no-tolerance mandrel, you'll no longer have to wonder.

 

[David Christian]

Is it necessary to use lube when using TN or carbide mandrels?

No lube of any kind needed with carbide pin/mandrel and brass goes not gaul.

 

[Ken6PPC]

I was wondering about this. Why is TN, black nitride, and carbide better for neck expanding? I understand the need for carbide for cutting tools, but brass over stainless steel seems to be enough right? I guess unless you are expanding a very large amount.

I only have ever used stainless steel and the expander plugs are just as nice as the day I bought them.

Not only is carbide slicker and creates less friction, the thermal coefficient of expansion is much lower. So, while a steel mandrel gets hotter than one of carbide, the steel one also expands more from that increased heat (per degree) than carbide does.

Carbide mandrels benefit not ONLY from less friction, but from better dimension stability than steel.

Edited to add:

What REALLY opened my eyes to this was the day I found my case necks turned at the end of my session the previous day were NOW a LOOSE FIT on the same mandrel that I had used the previous day, while I had made NO ADJUSTMENTS!

Then, I confirmed with the case neck micrometer that the necks WERE slightly thinner than the ones that had been turned earlier in the day with the same steel mandrel. I found that I could minimize those differences in thickness by placing the entire turner in the bucket of room temperture water for three minutes before turning the next case.

Since the water cooling really wasn't acceptable to me, I found that a carbide mandel didn't require such extreme efforts to stabilize between cases. Been using (or trying to find) carbide mandrels ever since!