Expander Mandrels- Mandrel Materials Importance?

[padom]

^ I picked up a new flyrod for me for Christmas. I had the foresight to pick something that I wouldn't be itching to use right now. ;-D

I hope it was a H3!?!?! lolol. And its Steelhead season, get out there!

 

[AZgeek]

Concerning this very subject, I'm in the process of trying out a different coating on an expanding mandrel.

Try Hexagonal Boron Nitride (hBN) powder. Put a little on a q tip and swipe the inside of the neck with it, I use it all the time when sizing my 50 BMG cases. Reduces the expander ball friction by at least 60% in my estimation.

 

[spife7980]

A sinclair expander has the same dimensions as a 21st century as far as fitting in the top goes. The Sinclair is a bit longer in overall length

 

[shotdown]

A sinclair expander has the same dimensions as a 21st century as far as fitting in the top goes. The Sinclair is a bit longer in overall length

Have you used it in the Sinclair Expander mandrel? I want to buy one for mine if it does.

 

[spife7980]

I have used the sinclair mandrel in the 21st century body and it works fine and the dimensions of the mandrels are the same so you could do the inverse as well.

 

[SPAK]

I just bought some TiN mandrels from 21st, they work just fine in my Sinclair die body.

 

[shotdown]

I just bought some TiN mandrels from 21st, they work just fine in my Sinclair die body.

Thank you

 

[918v]

I bought a sinclair expander just to compare the sizes to the 21st century and get an empirical measurement for us, Ill update after christmas when I get them side by side. I knew I should have just gotten them for myself and skipped this waiting on santa.

Got mine. They mic .307+ and .223+ not like they told me over the phone

 

[spife7980]

Got mine. They mic .307+ and .223+ not like they told me over the phone

And that’s the turning? Or the expanding? Those sounds like the claimed expanding dimensions

 

[918v]

Expanding.

The man said .306” and .222” for the expanding. Maybe he meant those were the plain stainless mandrels. The TiN coating must add .001” or so.

 

[Papagallos]

Turning Mandrel gives .002 neck tension, Expander gives .001 neck tension.

Would this even matter if you use a bushing die? I should state that I only use the expander mandrel to uniform bent case mouths. I don’t turn the necks.

 

[canezach]

Would this even matter if you use a bushing die? I should state that I only use the expander mandrel to uniform bent case mouths. I don’t turn the necks.

I think so, but that might be my own reloading OCD kicking in. Bushing sizes the neck down to X and leaves the outside of the neck round, so any slight imperfections are pushed to the inside. Running the mandrel through the mouth ensures the inside of the neck, which is gripping the bullet, is perfectly round.

 

[spife7980]

Would this even matter if you use a bushing die? I should state that I only use the expander mandrel to uniform bent case mouths. I don’t turn the necks.

That depends on your bushing selection and your neck tension goals.

 

[Papagallos]

Would this even matter if you use a bushing die? I should state that I only use the expander mandrel to uniform bent case mouths. I don’t turn the necks.

Since I use a bushing that gives me .002” tension, using a turning or expander mandrel shouldn’t matter because of the bushing, correct? I’d rather use an expander mandrel to ensure that I uniform the bent case mouths as best as possible.

 

[spife7980]

Would this even matter if you use a bushing die? I should state that I only use the expander mandrel to uniform bent case mouths. I don’t turn the necks.

Since I use a bushing that gives me .002” tension, using a turning or expander mandrel shouldn’t matter because of the bushing, correct? I’d rather use an expander mandrel to ensure that I uniform the bent case mouths as best as possible.

In that case not really. But as canezaxh said, if you’re using cheap brass the outsides of the neck will be even but all of the inconsistencies are pushed to the inside. The mandrel will push those to the outside but you would need to size down a bit more so that the mandrel has some dimension to actually work with. If you’re using turned or lapua etc that has a good consistent neck then no, it won’t really matter at all.

 

[spife7980]

Finally got around to remembering to do this, taken with a Mitutoyo caliper (.0005 accuracy ) and rcbs micrometer (.0001 accuracy). (Though my mic touch is admittedly poor)

21st century TiN
22 cal turning mandrel
.2220 on the cal, .2222 on the mic

21st century TiN
24 cal turning mandrel
.2405 on the cal, .2409 on the mic

Sinclair stainless
27 cal turning mandrel
.2745 on the cal, .2748 on the mic

21st century TiN
30 cal turning mandrel
.3055 on the cal, .3057 on the mic

 

[Beneviolence]

The short of it is that, if the material under the PVD process is polished well enough (prior to deposition), it can be much better than carbide (either carbide containing steel or CoCr-C HVOF). Amongst the PVD coatings, DLC (a diamond-graphite 'mixture) will be the best; followed by TiN, TiCN, and then the complex ones like AlCrTiCN, but it really depends on what settings are used in the HPPMS system. Dry lubes like Mo2S will significantly help as well. Careful on the PVD processes though; it can possibly change the dimensions of the substrate material from the high temperature exposure.

 

[BullzeyeNJ]

I have the 21st century TiN turning mandrels for 223, 6mm, 6.5, and 308. Just started using them this month to get uniform neck tension. I am using a Redding bushing sizing die first without the expander ball. I set neck tension .002” less then the outer neck diameter of a loaded cartridge. These are the instructions from Redding. The problem I am running into (sometimes) is that I am getting distinct belling at the top of the case mouth after I use the mandrel. This happens about 10% of the time. Any clue as to why this is happening ? I am thinking the inner neck diameter may by too tight for the turning mandrel and I get deformed belled brass as a result.

Any suggestions ?

 

[SPAK]

The belling is likely from the bushing...

 

[918v]

Maybe the mandrel is hitting some of the case necks off center due to misalignment between the case, she’ll holder, die, etc. Sometimes a case has a defect in the rim that prevents it from centering itself in the shell holder.