Is the expander ball needed?

[kentuckyMarksman]

I have been using the same RCBS 308 Full Length resizing dies for more than 10 years, and have never looked into using anything else. Today, I was resizing some brass for an upcoming match, and my expander ball came off the rod and got stuck in a case. It also stripped the threads on the rod, so it's toast.

I use an ultrasonic to clean my brass, and I deprime my brass before cleaning it using a decapper die. I'm not worried about not using my resizing die to deprime any brass... But my question is, is the expander ball necessary?

I don't know anything about expander mandrels, are they worth looking into? Or should I just buy a different die? Any recommendations?

 

[Yerman]

For precision reloading, a lot of people, including myself, believe that pulling an expander ball back through a neck can slightly change the headspace of the cartridge. For this reason, a lot of people will remove the expander ball on their sizing die and run a mandrel instead. However, it all depends on your brass and dies.

For example, on my 300NM, I use a bushing die which gives me the exact amount that I want to size the outside of the neck, but then use the Whidden expander ball kit to get me about half way to my final size. A neck turning mandrel takes it the rest of the way. On my 375CT and 6.5CM, I full size without a ball, and use a neck turning mandrel to get me to final size.

To answer your question, something is necessary. I don't believe in only using a bushing because inconsistencies are pushed to the inside of the neck and I want any inconsistencies on the outside not touching the bullet.

For your case, since you are not using a bushing die, your options are either new rod/ball, or get a mandrel. I'd invest in the Sinclair mandrels. Expander mandrel if you want .001 under, neck turning mandrel if you want .002 under.

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[straightshooter1]

I have been using the same RCBS 308 Full Length resizing dies for more than 10 years, and have never looked into using anything else. Today, I was resizing some brass for an upcoming match, and my expander ball came off the rod and got stuck in a case. It also stripped the threads on the rod, so it's toast.

I use an ultrasonic to clean my brass, and I deprime my brass before cleaning it using a decapper die. I'm not worried about not using my resizing die to deprime any brass... But my question is, is the expander ball necessary?

I don't know anything about expander mandrels, are they worth looking into? Or should I just buy a different die? Any recommendations?

No, the expander ball is NOT necessary. I full length size my brass with none as I use an expander mandrels after sizing. I do this as this method produces necks with little runout where expander ball tend to induces quite a bit of neck runout, which typically transfers to the bullet runout. Whether or not going this route is worth it, really depends on the type of shooting you do and just how much precision is important to you.

Here's what I use:

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SINCLAIR INTERNATIONAL CARBIDE EXPANDER MANDRELS | Brownells

Sinclair Carbide Neck Expander Mandrels are ground from solid carbide stock, which yields closer tolerances and more lubricity. Carbide is also better at resisting galling which can leave behind material and scratch the inside of your necks. The s...

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BTW: The reason I use carbide mandrels is so I don't have to deal with lube and they're tough and last forever.

 

[Yerman]

Also, consider dropping the wet cleaning from your process and replace it with treated corn cob in a tumbler. Wet cleaning gets the brass too clean and removes the carbon from the inside of the case neck that acts as a lubricant. That's likely why your expander ball finally gave way.

Also, dry tumbling is a lot easier to deal with and you will probably find that your sizing process is easier and more smooth with a little carbon on the case.

Lastly, the mandrels from Sinclair free float a little so you typically see a little less runout.

 

[Gustav7]

Big Fan of mandrels here. I have 3 Sinclair bodies now, and have used the Sinclair and the 21st mandrels, preferring the 21st mandrels, especially the new black nitride ones.

I shoot a lot of gas gun, so necks/mouths get dinged and the mandrel is great for cleaning that up quickly, and they do produce great neck tension once you get your process down.

 

[kentuckyMarksman]

Thanks for the info! I'm going to get the mandrel from Sinclair.

I do like shooting for precision (best I can with my factory Remington barrel). I'm thinking the Carbide Expander Mandrel is probably my better way to go.

I don't turn the necks on my brass (honestly, I'm a real amateur, I don't even trim my brass). Would the neck turning mandrel offer me any benefit over the carbide expander?

 

[Yerman]

Expander mandrel if you want .001 under, neck turning mandrel if you want .002 under.

 

[Gustav7]

Thanks for the info! I'm going to get the mandrel from Sinclair.

I do like shooting for precision (best I can with my factory Remington barrel). I'm thinking the Carbide Expander Mandrel is probably my better way to go.

I don't turn the necks on my brass (honestly, I'm a real amateur, I don't even trim my brass). Would the neck turning mandrel offer me any benefit over the carbide expander?

I would not recommend the Stainless, so you can pony up for the Carbide or you can get the expander mandrel from 21st century. I believe they have Titanium Nitride and Black Nitride. Come to think of it, I think brownells has the Tit/Nitride available from Sinclair as well.

FYI... both companies mandrels will work with the Sinclair or 21st Body. I have both mandrels and they work fine.

Expander Mandrel = 0.001" below bullet diameter (I.e. .224 bullet means expander mandrel is .223") With brass springback this usually always gives me 0.002" neck tension which is what I run on most my guns.

Neck Turning Mandrel = 0.002" below bullet diameter (I.e. .224 bullet means Neck turning mandrel is 0.222") With springback this will give around 2.5-3 thou of neck tension, which I use for one of my gas guns.

 

[kentuckyMarksman]

Thanks, I mainly load for bolt guns, so I'm going to try the Expander mandrel. You're explanation makes sense.

I'm going to get the carbide.

 

[color_me_gone]

Well, I have what I think is unique, at least to me. I was using a 308 Winchester RCBS FL sizing die w/ expanding ball. On the down stroke all went well but on the upstroke as the expanding ball was being pulled back through the next the 308 Winchester case split almost in half leaving the brass stuck in the die and I can not get it out. I tried a punch and tried freeze the brass but not the steel die. I cannot get it out. Is there any ideas or is there a chemical I can but that'll eat the brass away without hurting the steel die. Or, am I just SOL and now have to but a news FL sizing die. Please advise.

 

[FLIGHT762]

Contact RCBS, tell them what happened, e mail the photos and send the die to them. The more you mess with it the more you could damage the die.

 

[color_me_gone]

Contact RCBS, tell them what happened, e mail the photos and send the die to them. The more you mess with it the more you could damage the die.

Okay, thankyou. We will call them tomorrow and hopefully they can get the brass out. OPPS, I forgot to ask. What makes the

RCBS 308 WINCHESTER SMALL BASE FL SIZER X-DIE any different than a regular 308 Winchester FL sizing die​