Sinclair Mandrel Die overview 

I have been considering these pushing expander practices more lately. I guess I've come to the realization that there is a tremendous amount of accuracy potential wrapped up in the conditioning of my brass. These videos help me realize this in ways I have not considered before. I know this video is dated and I am weighing in late here, but I just wanted to give you a shout-out for these videos! It is a valued sacrifice of time, coin, and resources to produce these uploads and I appreciate them. Thank you!

I have the Sinclair expander die/mandrel to open the neck on 6.5x284 brass to .284(7mm). Works great! Great video! Thanks!

Heard about this from the modern day sniper pod cast, Scott satterlee mentions the mandrels benefit over a bushing die in that it doesnt have the potential of creating a doughnut in the neck. Sounds worthwhile to me!

An additional benefit, of mandrel sizing that many have missed. If you do not neck turn your brass, standard sized neck in chamber. There is another reason you use the mandrel to expand the neck The thickness of the neck varies, after using the mandrel, all those variances are on the outside of the neck, to be turned off, if turning, the inside of the neck is concentric. Using the mandrel die as a neck sizing die does the same thing with unturned necks. The surface that contacts the bullet(inside the neck) is concentric for consistent contact. When sizing with a bushing, the variances are pushed to the inside of the neck by the concentric bushing. I can very easily tell the difference when seating bullets in unturned necks. The effort or pressure to seat the bullet is very consistent. No more sorting match ammo into match and sighter's by feel of seating, they are all match ammo.

I just finished watching your Ultimate 6.5 Sizing die Comparison video and this one. I couldn't agree more with you on the value of the Sinclair Expander Mandrels and die. Of the 90 die sets on my shelf, many have the decapping stem removed completely and thusly makes sizing/expanding a two step process. It's really not a big deal. I set up both dies in a little Lee turret press or even my Hornady LNL AP. I can get the sizing and expanding as well as priming done all at the same time. I'd be lost without my Sinclair Expander set. Good videos.

Excellent! One another important point...lube the case necks. From Sinclair: "Be sure to lube the inside of the case neck before running a piece of brass over the mandrel. This can be done with a cotton swab or by dipping the case mouth into the lube. We recommend using FP-10, any of the sizing die waxes, or any sizing lube (Redding, RCBS, Rooster, etc.)"

Started off knowing nothing about the tool I feel like I could educate the manufacturer now! Haha great video dude

Now have one of these and the mandrels for 338 and 6.5.. Thinking of going with the forster fl dies and mandrels for all my calibers.

This is all very fascinating. I would like to see a test between ammo made with the expander die and ammo made with a regular full size or neck size die to see if it makes a difference in accuracy that is statistically significant using at least 20 pieces from each group. It already takes a very long time to make rounds, but I would add an extra time consuming step if it meant a better accuracy. I know you already have a lot of tests you want to do and will understand if you can't test this. Keep up the good work.

Thanks for this video! Big help

If you are using a Lyman M die to ezpand/flare case mouths for pistol, you are essentially doing this process already, this just isn't a 2 step expander. That was how I found out the benefits of it, by using custom sized M-die expanders for cast bullets. It makes case expanding sooooo much easier, even though it is an extra couple of steps, but, they are pretty quick. No fighting with scraping the neck across the expander ball in the die and pulling on the case neck, helps with case neck stretch due too sizing over an expander ball and reduces some trimming, and maybe some runout. just a better method in many ways. Some die stems let you remove the expander and keep the decap pin, some you can buy a cap to do that, or you can also use a dedicated decap die, or you can hit your expander ball with a file and take it down to undersize, or swap it out with a smaller one that you can either buy of pilfer from another die. Shud also have a look at this vid, in case you get OCD doing this; ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-sdJeADnU4Uk.html

I had not seen these before. Thanks!

G’day legend , I just bought my first Sinclair Mandrel die and a .307 SS expander mandrel and a . 306 neck turner mandrel for my 308 Win Police rifle . This is my first time using the Sinclair Mandrel Die. I’m using brand new Lapua 308 Win brass . After resizing the cases in a Redding FL die with the expander removed , i lubed the inside of the case necks and ran them into the Sinclair Mandrel Die thinking that the inside neck diameter would be about .307 for 0.001 neck tension but I was surprised to find that the inside neck diameter measures .304 to .305 because of brass spring back . My question is will the case have less spring back after a few firings so I can get a 0.001 neck tension when using the 0.307 SS mandrel or 0.002 neck tension when using the SS .306 turning mandrel ? Keep up the great content. We all learn a lot from content creators such as yourself to help us make accurate dependable loads for hunting and target shooting. Cheers 🍻 🍻

One thing to add is Zediker mentions the need to clean the expanders regularly. He polishes his and says you can't use too much lube (Imperial sizing wax) with them.

Great video. I've been handloading for years and thought I knew everything. I don't.....

Your videos are excellent; thank you. You mention in several of your replies that you use the NT mandrel. Do you use the stainless steel or carbide NT mandrels? Thanks in advance.

First and foremost - I love your vids and the way you deliver the content. I had 3 questions (if I may). 1. I have been considering purchasing an expander mandrel die to open the case mouth ever so slightly for the purpose of uniformity, however, I was wondering if this would help with the overall performance of the load? 2. I reload for my 6.5mm and have been experiencing some inconstancy in my seating depths (I have used various seating dies) and believe it may be due to various bullet sizing - I was wondering if you could kindly make any recommendations so that I can achieve more consistent ('accurate') seating results? 3. I also have a Hornady NT tool and was just curious if you're using the actual mandrels that it comes with or Sinclair ones? It comes across that Sinclair ones are being used? Maybe I have misunderstood. I REALLY appreciate your time in advance! Cheers, Dan

What's the difference between a expander mandrel vs the neck turning mandrel besides the size?

Your explanation of the equipment was very thorough and clear. However, I am still confused on the practical application for the reloading process. So for example, let's say I have a standard $35 2 piece deprime and full length resizing die. How is this piece worked in to my process? It sounds like I would remove the carbide from the full length resize, run the brass though the full length resize and them run them through this?

Great information!

Please show us how to set it up and perform the operation!

Does the Sinclair die work with the 21C mandrels?

For my 223 ftr rifle I use a .2245 mandrel for .002 tension, so your .337 would give you about .003 because of spring back

How many different mandrel companies are there, and what are the differences? If you know.

What are your thoughts on an S type bushing die to set neck tension based on the chamber from the outside, vs the mandrel which sets tension based on bullet diameter from inside?

Did you check the concentricity on finished brass with a mandrel vs. a regular or bushing die?

I have these for my neck turner, but I have never considered using them for final neck tension? Do you get measurably better concentricity this way? Thanks for the video!

Has anyone got any feedback on 21st Century Black Nitride mandrels?

This has probably been mentioned before but what if you used say the hornady custom FL die with the expander ball removed and then use the lee neck sizer? Would it be the same as this?

I use this mandrel on new brass with imperial dry lube and get extreme galling. I lube every neck and after just a few cases I need to dismantel and clean the brass build up off the mandrel with very fine wet dry abbrasive paper. I have similar results with a wet lube. Does anyone have any advice? Its driving me nuts!

Gday mate I had a few questions. So I have a mandrel die I think it's a 21 Century version as I have their neck turning lathe for mainly for my 243wssm which I have a custom tight neck chamber that requires neck turned brass. So before you use the expander/turning die for case necks, do you run your brass through a neck sizing die and if so what particular neck die do you use E.G. Forster without the expander rod fitted??? Would you use a Bushing type die to pre size before running through Sinclair expander die???? Does knowing your specific rifle chamber dimension determine how thick you have your cases or how much to neck turn them by???? Also should you always BUMP your cases E.G. 001-003 thou each time you resize/reload using either full length or neck sizing????? I saw a video on pressure/velocity variation just by bumping your cases too much. Four were bumped 001 thou and one at 005. AMAZING the difference. I know the theory of just neck sizing is less case working. I saw the video on Full length Vs Neck sizing which was great. So when you use the EXPANDER for neck tension what is your steps involved please?????? Thanks for the videos mate. They help you think about what you want to achieve and the ways you can approach it.

So I have a 6.5cm in an ar10. What would you suggest the .001 expander or the .002 turning mandrel for bullet seating tension?

Hab2e you fooled around with say a REDDING FL bushing die, remove expander and bushing so it just sizes the body. Then use the Lee collet sizing die? Oh wait then the shoulder won't get bumped back right?

What about case bounceback?

I bought a Redding full sized bushing and interested in getting a mandrel die. Which neck bushing do you use for your 6.5 creedmoor?

Thanks! Nice video Should I be full resizing after every time I shoot?

What do some of you think of sizing with a regular die then use mandrel to open case more, then seat a bullet?

Which Zediker book covers this?

I picked up one of these in kit form, it gives you 3 calibers to choose from to make up your kit, it's a good deal. K&M also makes a kit, which is worth looking at. Comes with 5 different size mandrels in it, just that each kit is caliber specific. If you have a minimum size neck in your die, you can set neck tension in .0005 increments with the K&M kit. Could give you more flexibility on neck tension than a bushing die, and it is cheaper. I was using two step M die expanders on one cartridge for cast bullets, and really noticed how much better they worked than using the expander that comes with the standard dies. It provoked the thought that I should do it that way on everything I have. kmshooting.com/custom-diameter-expand-mandrel-kit-for-bullet-tension-main.html

I don't get why I'd need something like this when I'm using bushing dies already.

Why do most of the calipers I see being used are cheap Chinese tools If you really want a true measurement use a quality micrometer, like Brown& Sharp or Starrett? Or am I being anal about this being an old Tool Maker?

I want so badly to like this channel. But i find so much of it incredibly annoying. From the endless footage of a wall, to the huge amount of words used to convey little information, the use of “guys” WAY too much, poor font choice, etc. Why put all those words on screen at once and on an overlay? Use a black background! Larger font and multiple pages! And after all this load development and huge amount of money spent on things like AMP annealer, the groups are overall not especially impressive. Sorry to be so harsh, please take this in the spirit of improvement with which it is intended.

lots of talk please show how it is used.

Are you still resizing using a bushing die and then last with the mandrel? If not how are you getting your neck back down so the mandrel will contact the inside neck?