Lee Universal Case Expanding Die

Most of us tend to muddle by, in our handloading, with the normal complement of tools to assist us: a press, die sets, shellholders, scale and a measuring device or two. As we become more sophisticated, we may add to this list. Lee Precision of Hartford, Wisconsin, has recently added a tool to its impressive line that may help us fine-tune our handloading even more: the Lee Universal Case Expanding Die.

What’s it for and why do we need it? Its purpose is to bell the mouth of a cartridge case without expanding the case neck. Need is perhaps too strong a word; facilitate might be a better choice. Before we get into specific examples of how it can assist us, let’s examine the tool itself.

It looks pretty typical: a cylindrical steel body about 3 inches long with 7/8x14 threads covering the lower 1 3/4 inches. Above the threaded area is a smooth section with “LEE - EXPANDR - L2” stamped around its circumference. Above that is a knurled section followed by another smooth section. An aluminum cap, called an adjusting screw, threads into the top of the body. A standard Lee locknut is used to secure the body in a press. Inside, the die body is smooth except for a threaded section at the top that accepts the adjusting screw. The smooth interior is of two diameters. The upper section will accept expander plugs of 9/16 (.5625) inch in diameter. A lower section is slightly smaller, preventing the plugs from sliding out of the body.

In use, one or two expanding plugs are inserted into the body according to the case to be expanded. A small plug has a cylindrical upper half and a tapered lower designed to accommodate cases of .22 to .32 caliber. A large plug is similar with its tapered section designed to be used with cases of .32 to .45 caliber. It appears 8mm cases would work with either plug, depending upon intent. The instructions are clear with diagrams and a chart that show how the plugs are to be assembled. With cases up to 1 1/2 inches in length, both plugs are inserted into the die body with the appropriate one taper end down. With cases from 1 1/2 to 3 inches in length, a single plug is used.

Setup and adjustment are simple. The expander plug, or plugs, are assembled according to the instructions and the adjusting screw is turned into the die body until the screw threads are below the die body surface. A case is placed in the shellholder and the press ram raised to its top position. The die body is screwed into the press until contact is made with the case mouth. The die body is locked in place. The press ram is lowered a bit, and the adjusting screw is turned in about one-half turn. The press ram is raised again, belling the case mouth. Fine tuning is done from there with the adjusting screw.

Now, back to when do we use it? I’ve encountered several situations where the new Lee tool was of use. The first was when I opened a bag of new cases purchased in bulk. Quite a few of the cases had mouths that were dented. Admittedly, some of the newer die sets have expander buttons with sufficient taper to straighten out the offending cases easily, but many do not. For me, it was easier to set up the new Lee Universal Case Expanding Die to straighten out the case mouths without lubricating, resizing or even actually belling the mouths. I was then able to chamfer the case mouths inside and out, as we should do, before beginning any loading projects.

Lee literature suggests using the die to bell case mouths prior to seating moly-coated or cast bullets. Even with some of the new chamfering tools designed to ease bullet entry, this may be good advice when using coated bullets with a two-die set, as is typical with bottleneck rifle cartridges. On numerous occasions I’ve seen the case mouth scrape off the moly coating as the bullet was seated. Whether this actually constitutes a problem in need of a solution will have to be determined by each shooter.

In the case of cast bullets, the situation is different. With the standard three-die set used with straight-walled handgun, and some rifle, cartridges, the use of the Lee die would be unnecessary. That is, unless you wanted the case grip to be that imparted by a sized but not expanded case. In that situation the Lee die could simply replace the second die, belling the case mouths but not expanding the neck area. This scenario is more likely to be appropriate with jacketed bullets than cast. It’s been my experience in working with a variety of expander plug diameters for a given cartridge that jacketed bullets benefit more from a tighter grip than do cast.

With two-die sets used with bottleneck cartridges, things change again. When shooting cast bullets, it is common to add an intermediate die that expands the case neck and bells the mouth. This is often referred to as an M die. Here again, if you’re using an M die, you don’t need the Lee. If you’re not, and the neck grip of the sized case is acceptable, the addition of the Lee die will aid bullet seating immeasurably.

Perhaps my favorite use of the new Lee tool is this: With some of my bottleneck cartridges I’ve been employing a full-length sizing die with interchangeable neck bushings. I get to custom control the amount of grip applied to the bullet and avoid using an expander button at all. With cast bullets I control the neck grip on the bullet with my choice of bushing and bell the case mouth with the Lee Universal Case Expanding Die. And I don’t need to buy an M die either. Bullet seating is greatly facilitated and the seating die returns the case mouth to normal, and even applies a crimp if desired.

You may even have a few uses of your own. Regardless, the new Lee Universal Case Expanding Die has earned a place on my bench. - R.H. VanDenburg, Jr.