For starters, this article is about how to use an expander die, and not about selecting your mandrel size; if you would like to read about that, click here.

Like most people, I initially went online to find out how to set up an expander die. Sometime later, I discovered that not only did the gentleman not know what he was doing, but I was surprised he could tie his shoes, much less upload a tutorial video.

Here is how to use an expander die? six simple steps

Step One:

Insert your desired mandrel into the expander die. Do not put the hat/cap back on the die at this point.

Thread the die shallowly into your reloading press with the lock ring at the top.

Step Two:

Please take out your set of calipers; it’s time to get a measurement.

Use a brass case and measure the neck’s length from the shoulder junction to the mouth. It would be easiest to use the depth meter on your calipers. (see photo)

Write that number down.

Example: 0.286

Step Three:

Place the case in the shell holder of your reloading press and raise the ram.

Next, thread the die further into the press until the back of the mandrel begins protruding out the top of the die. Now, back off slowly until the mandrel falls back into the die.

The more you turn the die clockwise into the reloading press, the more the back of the mandrel will protrude out the top.

What is happening in your case is that the mouth is pushing your mandrel out.
When it just makes contact, you are at zero.

Step Four:

This is where the previous measurement comes into play. You can now decide how much of the neck you want to be expanded.

I prefer my neck to be expanded 2/3 of the way down. Therefore, I will be using that mathematical equation in the example.

Example:

3 / 0.286 = 0.95

0.95 x 2 = 0.188

Since I only want to expand 2/3 of the way down the neck, 0.188 is my target number.

Step Five:

Using the depth gauge on your calipers and your target number, measure the mandrel’s back protrusion until it reaches that number.

Example:

When 0.188 of the back of the mandrel sticks out, I have hit my target.

Step Six:

Lower the ram on the reloading press.

Hold the die in place using one of your hands, and use your other hand to thread the lock ring down until it touches the reloading press. Then, tighten the lock ring.

Finally, place the hat back on top of the die. You are good to go.

Conclusion:

The cool thing about this is that your expander die is perfectly set up. You will never have to do this again unless you switch your caliber. I think the saying is, “Set it and forget it.”

I realize that this tutorial seems overly complicated. It’s just one of those things—after the first time you do it, you say to yourself, “Oh, that was easy.”

Yes, I could have simplified it, but I wanted it to have enough detail that even my special cousin Skippy, the paint eater, could figure it out.

Have fun, and remember: Shoot better than me. Mac R

Disclaimer: Reloading/handloading can be hazardous to your health like many things in life. You take full responsibility when performing these procedures. 5 Gun Nation is not liable for your decisions. Don’t be an idiot, and if you are, it is not our problem.

5 Gun Nations How-To series