Sinclair Turning Mandrel question

[copperking81]

I'm looking at picking up a Sinclair Expander Die Body and Sinclair Turning mandrel. This is the mandrel that is .002 inches under bullet seating diameter.

I want to use it for the sole purpose of expanding case necks after they've been sized with the expander ball removed.

With that in mind, I'm not sure if I should consider the stainless steel or carbide mandrels. It sounds like carbide comes in handy if you're actually turning necks (heat resistance, etc) and I'm not sure there would be any benefit to having a carbide mandrel for my purpose.

But I don't know...what say you guys who've used these before? Would there be some other benefit to the carbide mandrel for my intended purpose I'm not thinking about?

 

[LHSmith]

I'm looking at picking up a Sinclair Expander Die Body and Sinclair Turning mandrel. This is the mandrel that is .002 inches under bullet seating diameter.

I want to use it for the sole purpose of expanding case necks after they've been sized with the expander ball removed.

With that in mind, I'm not sure if I should consider the stainless steel or carbide mandrels. It sounds like carbide comes in handy if you're actually turning necks (heat resistance, etc) and I'm not sure there would be any benefit to having a carbide mandrel for my purpose.

But I don't know...what say you guys who've used these before? Would there be some other benefit to the carbide mandrel for my intended purpose I'm not thinking about?

No lube should be needed saving a cleaning step, and finished neck dimension should be more consistent with carbide (no variability in lube and cleanliness of mandrel- i.e. brass build-up)

 

[copperking81]

If lube is needed for stainless steel and not for carbide, even just for expanding, that right there is enough to push me to carbide.

 

[mikecr]

I agree on the carbide. It's worth it.
These will work with Sinclair die (or just use theirs, it's the same): http://www.pmatool.com/carbide-exp-neck-up-mandrels/

 

[rardoin]

I have used stainless expanding mandrels and lubed the necks with graphite (Imperial dry lube media kit) and did not have galling issues. I was only expanding less than 0.002" in all instances and mostly 0.001".

 

[Cowtownup]

Is anybody actually doing what the OP is stating he is going to do and having good results? I've messed around with doing this some on my 260 Remington and the results were not what I had hoped for.

My fired brass measures .297 outside neck
FL size without expander yields .289 outside neck
Expander Mandrel brings it back to .2915 outside neck
Loaded round is .293 outside neck

The math and measurements look great to me.. .0015 neck tension is exactly what I had when I pulled the button thru on my FL sizer die.
One thing I noticed when using the expander mandrel is that you can make 1 pass (pull of the handle) with it and the neck springs back some but you can make 3-4 passes and it feels like it relieves the spring back of the brass. Also, my findings show that sinclair's turning mandrel will leave you with about 4 thou of neck tension as compared to the expander mandrel which leaves you with 1.5 thou neck tension.

Can anyone elaborate on their method for setting neck tension with an expander mandrel?

 

[copperking81]

Is anybody actually doing what the OP is stating he is going to do and having good results? I've messed around with doing this some on my 260 Remington and the results were not what I had hoped for.

My fired brass measures .297 outside neck
FL size without expander yields .289 outside neck
Expander Mandrel brings it back to .2915 outside neck
Loaded round is .293 outside neck

The math and measurements look great to me.. .0015 neck tension is exactly what I had when I pulled the button thru on my FL sizer die.
One thing I noticed when using the expander mandrel is that you can make 1 pass (pull of the handle) with it and the neck springs back some but you can make 3-4 passes and it feels like it relieves the spring back of the brass. Also, my findings show that sinclair's turning mandrel will leave you with about 4 thou of neck tension as compared to the expander mandrel which leaves you with 1.5 thou neck tension.

Can anyone elaborate on their method for setting neck tension with an expander mandrel?

Unfortunately I cannot. However, I did take the plunge and purchased a Sinclair Expander Die body and one carbide expander mandrel to use as a test before I expand the practice to all my other calibers.

I'll see what the spring back looks like after one pass and then again after multiple. I would think an expander ball would be just as susceptible to that too though.

As far as the difference in the advertised neck tension and your benchtop results, I too have been concerned about that possible outcome. You're the first report I've read that identified it as a problem but I haven't found many forum reviews on the web discussing this practice either. I guess I'll see here shortly.....

 

[chkunz]

I have used both, the Sinclair turning mandrel and the expander mandrel for expanding necks. For this application I have not found a difference between the steel and the carbide options but have not done a lot of experimentation. I find that the turning mandrel leaves too much neck tension (interference fit) for some applications but the expander mandrel is just about right for most. All brass is not the same and there are tolerances with the mandrels that are a factor and I have found times when I would like to have had a expander mandrel that is just a little (~0.0005) larger.

 

[nmkid]

I have used their stainless for years and have never had any galling problems. I am not stingy with the lubricant. However, I do have to spend time afterwards and use a Q-tip to clean the inside of the neck and the area just where the neck starts.

 

[Cowtownup]

My rifle was shooting 3/8 to 1/2 minute using my regular reloading routine. What little bit of testing I did with the expander mandrel resulted in just over 1/2 minute 10 shot groups. However, I noticed my SD went from 5-6 FPS up to just over 10 and my ES was elevated also. Keep me posted on your results...

 

[noload]

I use carbide (T) for turning and (E) Expander mandrel for setting neck tension. I'm fortunate and have a lathe to turn lot of odd size mandrels from SS. With the carbides costing over $50 ea., making my own from stainless helps.

 

[copperking81]

My rifle was shooting 3/8 to 1/2 minute using my regular reloading routine. What little bit of testing I did with the expander mandrel resulted in just over 1/2 minute 10 shot groups. However, I noticed my SD went from 5-6 FPS up to just over 10 and my ES was elevated also. Keep me posted on your results...

I'm hoping for better results. The neck concentricity I get is terrible right now and I'm hoping the mandrel drastically improves it. I'll keep you posted on my results and conclusions.

 

[copperking81]

Is anybody actually doing what the OP is stating he is going to do and having good results? I've messed around with doing this some on my 260 Remington and the results were not what I had hoped for.

My fired brass measures .297 outside neck
FL size without expander yields .289 outside neck
Expander Mandrel brings it back to .2915 outside neck
Loaded round is .293 outside neck

The math and measurements look great to me.. .0015 neck tension is exactly what I had when I pulled the button thru on my FL sizer die.
One thing I noticed when using the expander mandrel is that you can make 1 pass (pull of the handle) with it and the neck springs back some but you can make 3-4 passes and it feels like it relieves the spring back of the brass. Also, my findings show that sinclair's turning mandrel will leave you with about 4 thou of neck tension as compared to the expander mandrel which leaves you with 1.5 thou neck tension.

Can anyone elaborate on their method for setting neck tension with an expander mandrel?

I got my turning mandrel in the mail today. Haven't had much time to really test it out but I did run a few cases through it. I got similar results as you did. Looks like it comes out to be 3-4 thou of neck tension. Concentricity has greatly improved though.

I'm going to test it more over the weekend and see what I get but the preliminary results suggest the expander mandrel might be a better choice.

 

[rgmeddn]

Different purposes.

 

[Ned Ludd]

I do it in the opposite order. I open up all the necks first to a minimum diameter larger than desired using the oversized expander mandrel (~.001 under caliber). Then I size them back down using a Redding Type S Match FL sizing die (no expander ball) and the appropriate bushing. This approach provides very consistent neck tension in my hands, especially with virgin brass. I have always used the steel mandrels with no issues, although if I was going to buy more at this point, I'd go with carbide for all the reasons mentioned above.

 

[jepp2]

The neck concentricity I get is terrible right now and I'm hoping the mandrel drastically improves it.

There are many things you can do to improve the neck runout with your current dies. So if your pursued path doesn't work out, you might want to try making changes to improve concentricity.

 

[rgmeddn]

There are many things you can do to improve the neck runout with your current dies. So if your pursued path doesn't work out, you might want to try making changes to improve concentricity.

Would you happen to know of a guide or perhaps a summary of the many things that can be done?

 

[jepp2]

Would you happen to know of a guide or perhaps a summary of the many things that can be done?

Most of what I learned initially came from the spiral wound book: Precision Shooting -Reloading Guide- written by Dave Brennan.

That got me started on my quest to reduce neck runout during the sizing and bullet seating operations. It was kind of a school of hard knocks and I know my experience is somewhat different than others. I tried a lot of things, measured the results and refined what I adopted. The way I routinely achieve case neck and bullet runout of less than 0.001" TIR:

1a. When full length resizing, I set the shoulder back 0.001" for bolt guns and 0.003" for semi autos. I make sure my case necks are only reduced enough so the expander increases the neck less than 0.001" in diameter. Bushing dies are the logical way, but I personally hone my die necks to the diameter I want. I just don't get as straight of necks using bushing dies.

1b. If I am only neck sizing I can always get my goal runout using a Lee Collet die. When full sizing if I haven't honed my die neck yet, I use a Redding body die (or S die without the bushing) for shoulder setback, then the Lee collet die for the neck portion of the case.

2. When I am using an expander (and I frequently don't) I set the expander high so it passes through the case neck just as the case neck leaves the neck sizing portion of the die. The case is better supported by the die at this point.

3. I lube the inside of the case necks if expanding and I use carbide expanders.

4. I use an O-ring under my die lock nut. I started doing this based on the theory that it lets the die center in the press threads more accurately. But I do it now because it makes small die adjustments for proper shoulder setback much easier. And the die doesn't move (change adjustment) during use.

5. For bullet seating I tend to use the Redding Competition bullet seating dies. But I have achieved the same low bullet runout with conventional bullet seating dies. I wait to tighten the bullet seating stem lock nut until there is upward force on the bullet seating stem while actually seating a bullet. I do all my bullet seating in a Forster Co-ax press.

6. I use the Sinclair concentricity gage for measuring neck and bullet runout. Accurate measurements require some touch for consistency.

 

[rgmeddn]

Wow! Now THAT was a Gold Medal Reply. Thank you so very very much!

 

[rgmeddn]

Found the book by Brennan. $150