Home Forums Hunting & Shooting Ask The Gunwriters Carbide expander button

I was given a Redding carbide expander button for a .308 caliber.
It is supposed to replace the regular expander button in my Redding .308 Win sizing die.
It is free floating along the shaft, supposedly centering itself in the neck and negates the need for lubricating your case necks before sizing. I never read about this on any posts and wonder if it is worth bothering with.
Does anyone have any experience with those carbide buttons, are there any downsides to them?
As is I produce already accurate loads for my .308 Win.

Generally they work very well--but have had a few not make any difference, usually in calibers much smaller than .30.

As always, any sort of expander-ball will work "better" (as in resulting straighter necks) if the brass has consistent neck thickness.

Expander balls also work better when they aren't having to undo the excessive sizing that the neck sections of dies provide for many types of brass. That's the downfall of any expander ball I put in my Redding FL die for 308 Winchester. It is a very tight necked die.

I've fitted quite a few of my standard Redding dies with the carbide expander buttons. They are easier on the neck I.D.'s and reduce the necks tendancy to end up canted a bit as they come off the expander. They don't completely eliminate the need for 'lube' inside the neck, though.....you can use a powdered graphite lube rather than a traditional lube like Imperial which is big upside.

With the carbide expander balls, it's actually better to not excessively brush clean the inside of the necks.....the powder residue acts as an additional friction reducer.

Good shootin' -Al

I recently got a new set of Redding.308 dies, having left my old set of .308 dies with my son, out in Missouri. It’s a “Premium” Deluxe die set (FL and neck sizers and micrometer seating due) . Like all my Redding dues, they are beautifully machined, really nice tools, but yes, they squeeze down the necks more than I would like. I communicated my concerns about it to Redding, but they are okay with it. My only.308 is a 1B, strictly a hunting rifle, so brass life is not a big concern or I’d probably open them up a bit.

Concentricity is affected as well as brass life.

Take about 15 minutes to address the excessive sizing issue. Five minutes to indicate it using a tight fitting pin gauge, one minute to open it up with a carbide reamer and 5 minutes to deburr it from the bottom. The other four minutes are for a couple sips of coffee.





Did a .17 Remington just recently...took it from 188 to .195. Worked great.

Good shootin' -Al

Thanks Al, I'll just pop over to the lathe I don't have in the shop I don't have.

I hear 'ya!

What size neck diameter do you want in the die? Let me know and I'll see if I have a reamer. -Al

.332" would be great.

Opportunity! Al's reaming service.

Don't they typically get lapped to size?

Just looked...no .332 reamer.

If you want to lap it, some pals have had very good luck with the Acro Lap barrel laps. It takes some time but is easily done with a drill at home. For your situation, the 5/16" would work as they will expand another 15% and get you to .332. A 'Q' letter drill bit is .332 so you could use that for a gauge if you don't have pin gauges.

https://www.penntoolco.com/acro-laps-for-high-speed-lapping-polishing-deburring/

Hope this helps. -Al

Dennis, yes they can be lapped as I posted. I've found a carbide reamer to be the best approach as the surface hardening of most dies is .003-.004 thick. Depending on the quality of the material the die maker uses, the carbide generally leaves a really nice finish even if it's removed the hardened surface layer. Some die makers use nasty material and depend on the hardened layer. Others use high quality material and high quality hardening.

At times, I'll quickly lap the reamed hole with some 600 grit compound...depends how it looks after the reamer gets done.

Good shootin' -Al