Expander mandrel

Bill Cauley Jr

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Is it normal for a carbide mandrel to get brass stains on it? I have the Sinclair units as well. When I was expanding necks in some Nosler once-fired 6.5-06AI cases with a .263 carbide mandrel, a couple of the necks actually collapsed during the expansion step. The cases were not salvageable. For the rest of the lot there was no issue seating bullets.
Necks must’ve been very tight maybe you should order a smaller mandrel and work up in two steps also you need to use lube if you’re getting brass sticking to the mandrel I occasionally polish mine off with 800 grit sandpaper I also use the dry lube which is basically graphite when using my mandrels
 

jimbires

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Is it normal for a carbide mandrel to get brass stains on it? I have the Sinclair units as well. When I was expanding necks in some Nosler once-fired 6.5-06AI cases with a .263 carbide mandrel, a couple of the necks actually collapsed during the expansion step. The cases were not salvageable. For the rest of the lot there was no issue seating bullets.


if you're using a bushing die , use a bigger bushing so you're not down sizing the necks so much .
 

AZShooter

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Read the entire thread plus the thread mentioned by Kwait40 on Accurate shooter.

Wondering:

Which lubricant is used with the mandrel and how is the residue in the neck dealt with after sizing?

If left in the neck I would think it could cause inconsistent bullet release. Tumbling could induce some neck runout. Annealing might cook it off. Would a solvent consistently remove the residue?

Perhaps if moly was used with the mandrel in conjunction with a moly coated bullet and no effort to clean the insides of the neck could resolve what I perceive as an issue?

Would love to hear the post mandrel regimen that others use.
 

BoomFlop

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I use Redding Imperial Dry Neck lube. I simply wipe the outside of the case off after running the mandrel in the neck. I leave it inside the neck as it makes bullet seating more consistent.

Powder contains graphite, so adding a minuscule amount of graphite in the neck should have no effect on burn rate. At any rate, as long as loading process is consistent, the effect (if one) will be applied to every round and thus be irrelevant.

Steve
 

J E Custom

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Is it normal for a carbide mandrel to get brass stains on it? I have the Sinclair units as well. When I was expanding necks in some Nosler once-fired 6.5-06AI cases with a .263 carbide mandrel, a couple of the necks actually collapsed during the expansion step. The cases were not salvageable. For the rest of the lot there was no issue seating bullets.
If the inside of the neck is very clean or powder fouled and the sizing mandrel doesn't have anything on it YES. carbide is very dense and highly polished so it has the highest amount of surface contact and can apply more force than the shoulder can stand in some cases. different cases are effected by the size of the shoulder. (I used to shoot handgun silhouette and used a 7 TCU, A 223 case necked up to 7 mm) and it had very little shoulder And I learned to lube the expander ball to prevent crushing the shoulder. The sizing mandrel is a good place to occasionally use the sizing wax. It will aid the sizing and prevent crushing the shoulders from to much force.

A little bit will go a long way. Be sure to clean the cases before loading.

J E CUSTOM
 

Frank Kalisz

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I use a 21st Century mandrel die with their TiN expander mandrel. It’s actually a pretty simple die so I cannot imagine how any other die of this type like Sinclair could be a problem. I use the Imperial Dry Lube graphite powder lube with its ceramic applicator pellets to make everything easy

post edit - I turn my necks to a consistent thickness, and I use a custom honed conventional Forster “Benchrest” full length die sized so that my mandrel doesn’t have to push neck out more than 1-2 thou. I run the Forster die without the expander spindle. Forster advertises a custom honing service for this purpose that is done at their factory.
 
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NelisB

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I bought this one recently, but I have not used it yet. It is a bit pricey, but good quality.

 

J E Custom

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The expander mandrel is the last step before seating the bullet?

It Depends how you use it. I use the expander "Mandrel" to size the neck for the turning "Mandrel" to better fit the turning "Mandrel" for a precision fit to turn the necks, This method has given me the most accurate neck thickness.

I have not tried using the sizing Mandrell for final neck tension. I consider this a separate operation than adjusting the neck tension. Also with the carbide sizing Mandrel, you cant make any small adjustments like you can with bushings or expander mandrels.

Then use a expander "Ball" in the dies or a bushing die to get the best fit for the bullet. Before any loading, the cases are cleaned.

Just the way I like to use the different mandrels.

J E CUSTOM
 
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nikonNUT

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I have a Sinclair carbide mandrel and die set-up and I really like it! Having said that there is a K&Ml in my future if only for the Over travel stop they offer. If you lack a light touch or lose focus you will slam the case mouth into the die body when it bottoms out and that can’t be good for the brass. Not a huge deal with some attention but K&M’s stop just makes sense and they can hook you up with a pin gage, etc., at the same time.

Edited... I meant K&M but MUCH love for 21st Cenfury stuff!
 
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Cdub338

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Rio Rancho NM
Hello everyone!
I need help selecting a good mandrel to be used as a final step before seating the bullet.
In my mind a mandrel has to have very low tolerances less then 1/1000 thou and be honed to have a very smooth surface.
I see the most popular is the Sinclair one but people are complaining about the quality. The carbide one seem to be good but can you polish carbide smooth the surface?
LE Wilson makes one and I just love it from pictures. It looks like it is polished like he is trying to make a mirror out if it. The downside's only half a thou under. Is that enough for a 300 PRC for hunting?
21st century has a good selection for each calibre in half a thou increments, but their website is atrocious can't tell from the pictures if I'm buying apples or mandrels.
What else is out there that if very good quality?
I’ve had really good luck with K&M products, there’s a little lead time, but the basics and everything you need to get started are available on Midway and such. I went down this rabbit hole specifically for my .300 PRC. Saved me shoulder bump using their tapered setups on the outside of the neck/shoulder as well, I deformed A LOT of brass trying to resize .375 Ruger.....

 

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