Do you skip the expander mandrel?

WTNUT

Lil-Rokslider
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Reloaded a ton for 20 years, didn’t do much for 15 or so, then had 5 years of a little more reloading. This year I have been at it full force more than ever. Maybe just getting to be one of those old farts who avoids people and sits at his reloading bench every evening. Ha Ha. Now the question.

I use a Redding Type S Full Bushing die 99.9 percent of the time. I resize between .001 and .003 like most. I probably go .002 most of the time. I have tried loads where I use an expander mandrel after resizing, and then worked the same load without the expander. I really don’t see any difference in accuracy (group size). Obviously this all assumes the brass passes inspection after resizing.

Do you always use an expander after resizing?


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WTNUT

Lil-Rokslider
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And for what it is worth, been fun to read your threads and see what the trends are today. Reloading preferences change a bit from decade to decade. But then again so did my wallet. 40 years ago I could have never afforded a competition seater.


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Article 4

WKR
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Using the redding bushing dies allows for complete control of the OD that you resize to. If your bushing is a larger size, and your brass is turned and consistently sized, it is possible to not run an expander mandrel. It is more difficult to ensure consistent pressure but if you are getting the groups you want, then go with it. It is likely putting less stress on your brass not expanding it back out.

Option - you could run an optional expander size. Most are available in 2 or 3 sizes within the caliber to accomodate different brass thicknesses so depending on your ID, you could run a Thou bigger or smaller and achieve what you want
 

wapitibob

WKR
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I run a turned down 30 cal expander to clean up any fired necks that may have been dinged but that's it. I step down neck bushings from fired and don't use a mandrel.
 

Jimbee

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I reloaded a hundred or so 6GT and forgot that I removed the expander button in my sizing die. Added powder and seated bullets. The shot well, no obvious difference.
 

Dmoua

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Depends what kind of accuracy you’re looking for. I always use one.
 
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I always set final ID with a mandrel. I don’t care about OD as there is sufficient room for the brass to expand to the chamber.

Unless you know the thickness of your brass at the neck you don’t really know the ID and amount of interference of your brass to the bullet.


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TaperPin

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I don’t use an expander button with neck dies, although if used, it wouldn’t be doing much. I’ve resisted a mandrel die to run down into the case to even out the neck after sizing, however, I will probably get one his summer just to try and see if it makes any difference with a couple of what I’m hoping are very accurate barrels. For 1/2 moa, it doesn’t take anything other than regular boring normal fl dies.
 
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WTNUT

Lil-Rokslider
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My best estimate is that the expander mandrel is the best approach for some of the reasons noted above.

I use a Wilson expander die and if my recollection is those are about .003 smaller than the caliber sized.


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Lawnboi

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I used to use a turning mandrel. I don’t like 1.5 thou of interference fit, which is what an expander mandrel gave me. I gave up on it because of the extra step involved.

Now I just expand, decap, and size in one step with a SAC die. Bushing 4 thou under, and mandrel 2 thou under bullet diameter. Leave me with 25 thou interference

My press gets pulled once for brass prep only, bullet seating I do with an arbor press.

Time saver and makes as consistent if not more than doing sizing and mandrel in separate steps.
 

J.Hunt

FNG
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Mar 3, 2024
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For an unusual application, I ended up modifying a small base 308 die with the expander removed. I sized a few hundred mixed head stamp miltary cases with no expander. Not something I would prefer to do, but I had no issues and accuracy was not affected.
 

BsDada

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Where you may see more benefit is due to velocity SD, which will turn into consistency at longer distances. Assuming only variable.
 

Vern400

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Neck sizing and not using a mandrel or sizing ball puts all the dimensional variation on the ID. So you get more variation in bullet seating force. That's if you are not already yielding the brass during seating. So your ES, and SD will probably increase. Especially if you're using not great brass.

Is it the one thing that's going to open up your groups by 3/8 inch at 100 yds over 10 shots? Probably not. But neither will cleaning your brass, deburring flash holes, cleaning primer pockets, weighing charges, sorting brass, annealing, sorting for concentricity, having a bubble on the scope, and so on.

It seems to me past 300 / 400 yards is where the details really start to matter for me. Then a case 0.013 thick one side and 0.016 on the other might be that flyer. It takes a lot of shots to verify the effect of small changes.
 

Harvey_NW

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I highly doubt you'd see a difference in precision at short range, but F-Class shooters like Alex Wheeler believes it makes a difference at 1k, and has recommended more like .004-5" interference fit for lots of modern cartridges.

I went full tilt down the rabbit hole with competition micrometer seaters, mandrels, neck turn, all of it. None of it made a measurable or repeatable improvement in my hunting rifles. I now just use standard FL die sets. I polish the expander down to .003" below bullet diameter, and use graphite lube in the necks before seating to prevent bullet weld. The idea of setting the ID with a fixed dimension to mitigate variations in thickness makes sense to me.
 

Jimbee

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I highly doubt you'd see a difference in precision at short range, but F-Class shooters like Alex Wheeler believes it makes a difference at 1k, and has recommended more like .004-5" interference fit for lots of modern cartridges.

I went full tilt down the rabbit hole with competition micrometer seaters, mandrels, neck turn, all of it. None of it made a measurable or repeatable improvement in my hunting rifles. I now just use standard FL die sets. I polish the expander down to .003" below bullet diameter, and use graphite lube in the necks before seating to prevent bullet weld. The idea of setting the ID with a fixed dimension to mitigate variations in thickness makes sense to me.
How do you use/apply graphite lube?
Thanks,
Jim
 

Harvey_NW

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How do you use/apply graphite lube?
Thanks,
Jim
I fluff up the cotton on a q tip, dip it in the media and tap the excess off, spin with my fingers and dust the inside of the necks in the case tray. I do 5 and then reload. It has totally eliminated bullet weld and vertical or pressure issues with ammo that's sat for a while.
 
Joined
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I fluff up the cotton on a q tip, dip it in the media and tap the excess off, spin with my fingers and dust the inside of the necks in the case tray. I do 5 and then reload. It has totally eliminated bullet weld and vertical or pressure issues with ammo that's sat for a while.

Another good solution here is Neolube No.2.


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