Precise Neck Expansion with Gage Pin Die from Porter’s Precision

Gage Pin Die System Product Review
by F-Class John
Consistent neck tension is often considered key to precision reloading. Neck tension (or interference as it’s more accurately known) helps ensure that the bullet is held with a known amount of pressure ensuring a consistent release each time. The more common expansion method employs expander mandrels. However, there is another lesser-known but very effective method — using GAGE PINS. This article reviews a unique Porter’s Precision Products Reloading Die designed to work with high-quality Gage Pins.

Gage Pins, long-time tool of machinists, are used to measure the size of a bored hole. They come in a variety of sizes and classes. In the reloading world, most people use ZZ Gage Pins that are sized .0005″ apart and are accurate to .0002″. The nice thing about Gage Pins is that you can order them in either a + or – size which means their accuracy errors on one side or the other so by ordering sets of + and – you can effectively make half-sizes. It’s this flexibility and great range of sizes that make Gage Pins so attractive.

For all the good that Gage Pins can do, until now there has not been a handy way to use them in a reloading press. Some folks tried using a bullet puller to hold the Gage Pin. But on many presses, this can be inconvenient because of long handles or unusual height requirements. As a result, I have mostly resorted to using conventional expander mandrels.

But now I have started using precision Gage Pins, thanks to a special new Gage Pin die system from Porter’s Precision Products in Texas. Not long ago I received a video from a friend showing someone using a custom die specifically made for holding Gage Pins. It turns out that Porter’s Precision Products out of Texas makes a custom Gage Pin Die product that consists of a die body, collet, and die cap. Porter’s Precision also sell a wide range of Gage Pins that have been nicely tapered to prevent damage to brass.

Using the Porter’s Precision Gauge Pin Die for Expanding Necks
Using the Porter’s Precision Gage Pin die is pretty straight forward with one caveat. The instructions are very clear that the collet must be inserted at an angle into the threaded cap to help ensure it tightens correctly otherwise damage to the collet may occur. Once you do this a couple times it becomes very simple and shouldn’t be a concern, especially since there’s rarely a ready to actually remove the collet unless you’re changing from one caliber range to another.

With the cap and collet now threaded onto the die body, choose the Gage Pin you want to use, insert it into the collet and tighten the cap down. Once the pin is where you want it, use a set of wrenches to firmly tighten the cap down and you’re ready to go. Thread the die in your press and simply adjust the height to ensure the Gage Pin is being inserted fully into the neck of your brass. You want to make sure the entire neck is being expanded without damaging the rim by pushing it to far up inside the die.

General Thoughts — Gage Pins vs. Expander Mandrels
The actual use of Gage Pins on case neck doesn’t vary from expander mandrels. They both accomplish the same goal and which tool you choose really comes down to personal preference. Where Gage Pins really shine is in their durability and the vast selection of sizes/diameters/tolerances. You can even find long-wearing, reduced friction carbide Gage Pins, but they do cost more.

For me, using the Porter’s Precision Die allowed smooth operation and Porter’s Gage Pins are really well-made. This makes expanding a dream even without any lube in the necks (although I still recommend lube when using a steel Gage Pin, as opposed to carbide). If you’ve been in the market for a way to help expand your necks with enhanced consistency, give Gage Pins a try using the Porter’s Precision Gage Pin Die.