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Mandrel in place of an expander ball?

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June 28, 2017, 08:39 AM
benny6
Mandrel in place of an expander ball?
So I'm getting the Redding bushing die set for my 308 soon. My current routine is to de-cap brass before cleaning and sizing, so I don't need a de-capping pin in my sizer die. I was thinking of removing the expander ball from my sizing die and using a Sinclair mandrel neck expanding die.

Thoughts? What size should I get and should I use the mandrel before or after using my resizing die?

Tony.


Owner, TonyBen, LLC, Type-07 FFL
www.tonybenm14.com (Site under construction).
e-mail: tonyben@tonybenm14.com
June 28, 2017, 09:26 AM
Expert308
The neck will expand under gas pressure when you fire the round. All you should need to do is run the fired case through the new sizer, it will return the neck diameter to the proper value. You shouldn't need to use an expander or mandrel at all, unless the case mouth gets dinged up during extraction. In that case I'd run a mandrel through it to return it to round, but do that before sizing.

As for the size, I'm not sure whether you're asking about the mandrel or the bushing. In either case, read through the first couple pages of NikonUser's "Handloading for precision/competition" thread, he explains it there and lists the part number for the .30 cal mandrel/die. I'd just tell you what mine are but I don't recall the number off the top of my head.
June 28, 2017, 09:44 AM
benny6
Thanks. I was asking about what size mandrel. I've got the right size bushing on order. If I have a dinged up case mouth, I may just run the case through my RCBS sizing die just far enough to run over the expander ball, then run the case through the bushing die.

Tony.


Owner, TonyBen, LLC, Type-07 FFL
www.tonybenm14.com (Site under construction).
e-mail: tonyben@tonybenm14.com
June 28, 2017, 10:19 AM
NikonUser
I decap my brass using my Redding bushing die. I removed the expander ball and I just use the little grommet in its place to hold the decapping pin.

I have a Sinclair mandrel on one of the stations of my Redding T-7 turret press and in the holder I have a Sinclair neck turning mandrel.

http://www.brownells.com/reloa...ndrel-prod33136.aspx

The model number is 749-001-184WB, it's a .306 mandrel.

Before I first use Virgin brass, I run all cases through the mandrel to take out all the dings and standardize the neck diameter.

After the first firing, I only use the mandrel on my brass if there's a ding in it. If it's before sizing (rarely*), I run the case right over the mandrel as usual. But if there's a ding after sizing, which will most of the time be a result of me dropping a case, I do it a little differently. I will slowly insert the mandrel into the mouth of the case until I feel some resistance. From there, I give it just a smidgeon of a nudge and then pull out the case. I don't want to run the whole neck through again, just fix the ding.

*Rarely: I feed my cartridges one at a time into my match rifle. It doesn't even have an ejector. I pick each fired case directly from the bolt face and deposit said fired case back into the ammo box, in its hole. I never accumulate brass or let it fall on the ground. That's why it's never dirty or dinged from firing.

If I were to get dings from firing, I would use the mandrel to repair the ones that are really bad but I would leave the others to be cleaned up by the sizing bushing. I can always adjust anything that looks askew after sizing. I would err on the side of caution if there were lots of dings and hits and probably mandrel a lot before sizing. Best to keep your fired brass safe, but that's not always possible.
July 01, 2017, 05:54 PM
exx1976
To round out dings in case mouths, I use a k&m expandiron mandrel. Same diameter as a bullet, and I only run fired cases over it. I use it only before annealing, and only in the cases that need it. Then I use a bushing FL die to resize before loading.


ETA: I thought I was the only one that dropped cases.. Lol amazing how quick that neck will ding up from only a 3' fall. And it ALWAYS lands on the mouth, never on the case head. Ugh.
July 01, 2017, 06:15 PM
NikonUser
Yeah, like buttered toast; always lands buttered side down.