A few weeks back I wrote about the comparison between a regular and dual-ring carbide dies for reloading (more specifically for sizing).

Earlier this week I was lucky enough to find the .40 S&W die in stock at Brownell’s for a few hours. I picked one up and it arrived today.

Here you can see both carbide rings pretty well.

I did experiments with both Winchester and Federal head-stamp brass to see a single-ring versus dual-ring dies for sizing and build up a few dummy rounds.

Here’s a dummy round from a single-ring sizer:

And here’s the same from a dual-ring sizer:

This was the Winchester brass. The others in the photo set are the Federal. The same effect is evident there too.

The difference is quite striking in my opinion. From checking it with the chamber gauge I could tell the brass grew lengthwise a few thousandths of an inch too.

Getting down to brass tacks (or, better brass cases):

Win 1-ring Win 2-ring Fed 1-ring Fed 2-ring Hornady (Factory)
Mouth .4205 .4205 .4205 .4205 .423
Waist .417 .423 .417 .423 .422
Head .422 .423 .420 .4225 .4225

(All measurements in inches)

Now these are sample sizes of one, so this is not scientific at all, but the end results are fairly conclusive regardless.

You can see both from the pictures and measurements that the waist of the cartridge is just plain over-sized-down by around 6-thousandths of an inch. It doesn’t sound like a lot… but it is a lot.

Here’s a comparison with the Hornady ammo:

Besides the chamber gauge, here’s the specs of the round:

All of my rounds meet the specs for the minimum chamber with ease.

This isn’t to say a regular sizer is going to make rounds that don’t work. It will — and has. I’ve made thousands of rounds with the old sizer. I’ve just over-worked the brass in the process.

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