Particulars Of Reloading For Semi-Auto Pistols

Gun News

Reloading for semi-auto pistols isn’t rocket science, but requires a solid understanding of the process to produce workable ammo.

What Are The Challenges To Reloading For Pistols:

  • The cartridges headspace off the case mouth, thus squaring the case mouth is imperative.
  • Length is also an issue, give they need to run smoothly through a magazine and still headspace once in the chamber.
  • A tapered crimp is required to hold the bullet in place and maintain headspace.
  • Not only does this require a special seating die or taper crimp die for the process.

These days, the ammunition shelves seem to be as bare as they’ve ever been. A few, short months ago both guns and ammunition were plentiful. The record gun sales—handgun, rifle, and shotgun—of April, May, and June, coupled with those who want to have an ample supply on hand, have seen ammunition flying off the shelf at an unbelievable rate. Simply put, factories just can’t keep up with demand.

Reloading Semi-Auto 3

More folks are turning to reloading to keep their firearms fed, and while that’s a sound means of keeping yourself in ammunition, there are some points to discuss when it comes to reloading for semi-auto pistols. Unlike the cartridges designed to function in the cylinder of a revolver—which more often than not use a rimmed cartridge—the semi-autos need a case that’ll feed reliably from a magazine. While there are many, the 9mm Luger, .40 Smith & Wesson, and .45 ACP are, inarguably, the most popular.

Pistol Case Headspace

All of these straight-walled, rimless designs headspace off of the case mouth (in theory). As a result of that design, I start with a good, square case mouth to help keep things running smoothly. Trimming cases to a uniform length—usually no longer than that length prescribed by SAAMI—is a good idea, so a good set of calipers or a case length gauge will be needed to verify the cases are of the proper dimension.

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The author keeps four dies in the turret press for .45 ACP ammo: the carbide resizing die, expander die, seating die, and lastly, the micrometer adjustable taper crimp.

If the cases are trimmed too short, they won’t headspace properly and might rely on the extractor for stability. This probably happens more often than you’d think, yet it rarely becomes a problem. If the cases have stretched and are too long, chambering could be a problem. SAAMI offers a certain tolerance level (+/- 0.010 inch in the case of the .45 ACP) for the ammunition, and the manufacturers have a tolerance for the chamber dimensions, so you might have to do some experimentation regarding the length that’ll work best in your pistol. At the very least, I feel comfortable using a case gauge, in order to weed out any potential problems.


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Tweaking the Taper

One important aspect of the straight-walled rimless cartridge is that they require a taper crimp in order to keep the bullet in place. Because of the means of headspacing, rolling the case mouth into a cannelure or crimping groove just won’t do. So, instead of using the seating die to both seat the bullet and roll crimp in the same operation, you’ll need a seating die when reloading for semi-auto pistols, which offers a taper crimp or a separate taper crimp die to squeeze the case walls around the bullet. This operation provides enough tension to keep the bullet from being driven into the case as it hits the feed ramp, as well as preventing the bullet from creeping out of the case and giving chambering issues.

Lee dies are both affordable and effective. While they might not possess some of the bells and whistles of other brands, they function properly.
Lee dies are both affordable and effective. While they might not possess some of the bells and whistles of other brands, they function properly and work for reloading for semi-auto pistols.

The amount of crimp applied to the case is—generally—calculated by adding the bullet diameter to the thickness of the case wall (times two for both sides), then subtracting 0.004 inch for proper tension, measured at the case mouth. Again, speaking in generalities, because differing brands might give different readings, case walls measure about 0.010 inch. So, looking at the .45 ACP, a good taper crimp would produce a loaded case measuring as follows: 0.452 inch for the bullet, plus two case walls at 0.010 inch each, minus the 0.004 inch for the taper crimp for a grand total outside dimension (OD) of 0.468 inch. For the 9mm Luger, you’d add the bullet at 0.355 inch, plus 0.020 inch for the two case walls, and subtract 0.004 inch for an OD of 0.371 inch. It’s a simple formula, but if the crimp isn’t coming out right you might want to examine the case thickness.

An overly taper crimped cartridge can actually crumple the case wall below the bullet, rendering that case useless, and if you’re using lead bullets, or even thinly plated bullets, you can deform the bullet to the point where accuracy becomes wild. If you use too light of a taper crimp, the bullet can move within the case, and that doesn’t work out well at all. That nice, square case mouth should end up squeezed against the bullet’s sidewall, and if you scrape it with your fingernail, you can feel the change brought on by the taper crimp. A properly applied taper crimp will also help to keep velocities more uniform.

Taper Crimp Dies

There are plenty of good taper crimp dies on the market; some come as part of a set, as in the RCBS seater die with taper crimp instead of roll crimp, and others are sold separately. The Lee taper crimp die is a popular choice. Among the conventional taper crimp dies, accurate adjustments can be a challenge at times. The 7/8-14 threads of a standard die can require several attempts at adjustment before you get things just right, and that can be a frustrating experience.

Redding’s taper crimp dies: The micrometer adjustable die is in the foreground, and the standard die is behind it.
Redding’s taper crimp dies: The micrometer adjustable die is in the foreground, and the standard die is behind it. This high-end option can provide a leg up when reloading for semi-auto pistols.

Redding saw the problem and, as usual, offered a sensible and reliable solution. The Micro Adjustable Taper Crimp die gives 0.100 inch, up and down, of adjustment without having to touch the lock ring. A blued, knurled adjustable dial—clearly marked and graduated—sits atop the die body, and I can attest to the fact that the crimp responds properly to the adjustment. If you segregate your brass, you can make an adjustment in crimp when you change brands, but I will tell you that it’s wonderful to just twist that knob to set things right again.

I find it amazing how fast our ammunition situation changed from readily available to nonexistent. But this isn’t the first time it has happened in the past decade, and it probably won’t be the last. Reloading ammunition might not be for everyone, but I’m starting to believe that it’s a skill every shooter should possess. With a good set of dies and some components, you can continue to train with your chosen handgun for relatively little money.

Editor’s Note: This article originally appeared in the October 2020 issue of Gun Digest the Magazine.

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