March 23, 2020
By Dave Emary
Reloading is a great hobby that can enhance your enjoyment of shooting through the making of your own ammunition, and it can save you money. It also allows you to optimize the performance of your firearm through the careful selection of components and custom reloading techniques.
You can find a lot of information in reloading manuals and books about the basic procedures, practices and equipment for reloading, but what if you want to get the most from your reloaded ammunition and the best possible performance from your firearm? What follows are several techniques and specialized tools that will enable you to load uniform and accurate ammunition.
Cartridge Case Preparation
The cartridge case is perhaps the most important component of a reloaded round of ammunition. It is the glue that holds all the other components together. The case is also the component that aligns the bullet with the bore of the gun. The trueness and consistency of this alignment has a major impact on the overall accuracy of the ammunition and rifle combination. You can load the most accurate bullets ever made, but if you put them in a crooked case that doesn’t align with the bore, you’d never realize how good the bullets were.
The case also holds the primer. Invariably, primer pockets and flash holes can adversely affect the ammunition’s performance consistency. With these in mind, there are some techniques and equipment that can be used to get the straightest cases possible with consistent dimensions, and the most steady overall performance.
The first thing to do with cartridge case preparation is to uniform the flash hole and primer pocket. A lot of cartridge cases will have a burr around the flash hole on the inside of the case. This burr can be small or can nearly cover the flash hole. The burr is a by-product of the production technique used to pierce the flash hole. It can cause inconsistent flash from the primer into the propellant charge. The use of a flash hole deburring tool will remove these burrs and improve the ignition and performance consistency of your ammunition.
Primer pockets are not always uniform in depth because of production variations. This can result in inconsistent seating depths of the primer, which can cause varying primer sensitivity and output. A primer pocket uniformer will cut the primer pockets to the same depth allowing consistent primer seating depth. Flash hole deburring and primer pocket uniformer tools are available from most of the major reloading tool suppliers.
The last piece of the priming equation is a ram prime system. These priming systems use an adjustable die in the head of the press that holds a shell holder for the cartridge case and a primer seating punch that fits into the ram of the press. This priming system allows very precise and uniform seating depth of the primers. Ram prime systems are available from Lee (leeprecision.com) and Lyman (lymanproducts.com). One note: the primer should be seated .002 inch to .005 inch below the head of the case. This must be done in order to obtain consistent primer performance by compressing the anvil into the explosive pellet in the primer. Seating primers deeper than this can crack the explosive pellet and decrease primer sensitivity and lead to inconsistent primer performance.
The ultimate goal of resizing a cartridge case is to obtain consistent case dimensions, headspace and the straightest possible case to serve as the backbone for the round of ammunition. One of the best ways to achieve this outcome is to use a bushing, match-grade-size die. This die design uses floating bushings to size the neck of the case. Hornady (hornady.com) has gone so far as to have a floating de-cap punch in their dies to prevent the spindle assembly from bending the neck of the case. A properly sized bushing allows a minimum of sizing of the neck and greatly extends case life.
Most solid dies excessively size the neck of the case in order to be able to size any neck thickness in a case. The floating bushing, and in Hornady’s die, the floating de-cap punch allow self-centering of the neck with the body during resizing. This produces a straight resized case. Bushing dies can be set up to allow only the use of the bushing for resizing the neck without the need for an expander. Using this technique can result in more uniform resized case headspace because of not having to pull the expander back through the sized neck, and risking pulling the shoulder out and changing headspace.
Full-length-size dies should be adjusted to provide a case with headspace of .002 inch to .003 inch below that of the fired case. Setting the die like this will minimize sizing and work hardening of the case and provide a minimum acceptable clearance between the case and chamber. The use of the Hornady Lock-N-Load headspace gauges allows you to precisely measure the headspace of your cartridge cases and set the dies accordingly.
For lubing cases, spray lubes allow uniform placement of lube on cartridge cases for resizing. If you are using an expander it is important to try to get some lube inside the top of the neck of the case to reduce the drag of the expander on the neck. Spraying cases from the open neck of the case is one way to do that. Make sure that you spray at an angle from above and not directly into the case. You do not want lube inside the case body.
A cheap and easy way to make expander extraction easier and more uniform is to purchase some graphite at a hardware store and put it in a cup. Dip the neck of the lubed cartridge in the graphite and then size your cases. You will find that the extraction of the expander is much easier and more consistent. This will also result in more uniform sized cartridge case headspace.
Lastly, keep track of the number of times your cases have been fired and resized. As the case is repeatedly fired and resized, the neck and shoulder gradually get more work hardened. This leads to a higher pressure that’s required to push the bullet from the neck. This is known as neck tension, and if neck tension is not consistent it will result in erratic ammunition performance, especially in pistol cartridges. If you have a mixed number of firings in a group of cases, anneal them all at the same time to get them to the same neck hardness condition.
As I discussed in my column on reloading for lever-action cartridges several issues ago, an easy way to anneal cases is to place then in a cake pan of water filled to a little below the shoulder of the case. Heat the necks and shoulder with a propane torch until they begin to turn color and then knock them over into the water. Annealing every five or six times the cases are sized will eliminate the tendency of necks and shoulders to crack because of work hardening. It will also greatly extend case life.
The final process in reloading a round of ammunition is seating a new bullet in the resized cartridge case neck. How the bullet is seated and the dies used to seat the bullet are critical to how straight the loaded round of ammunition is. There may be other nomenclature, but I have always called the misalignment of the bullet with the axis of the cartridge case a “loaded round runout.” To achieve the best performance of your ammunition, the runout between the bullet and case must be kept to a minimum. If you roll a round of ammunition on a flat surface and see the bullet “wobble,” you have loaded round runout. The best way to reduce runout in the loaded ammunition is to use a seating die with a floating alignment sleeve and seating punch. The alignment sleeve captures the neck of the cartridge case and controls the alignment of the bullet, neck and seating stem while the bullet is seated. The tighter fitting the alignment sleeve with the neck of the case, and the tighter the fit of the alignment sleeve and seating stem, the lower and more consistent runout your ammunition will have.
Many die manufacturers will make a custom seating stem that precisely fits the shape of the ogive of the bullet you want to load and further improve the runout of your loaded ammunition. Hornady offers custom seating stems for most of their match bullet lines. One other simple trick that can help to reduce runout is to just barely start the bullet in the case, lower the ram and turn the case 180 degrees in the shell holder, then finish seating the bullet.
One of the best tools I have used to improve the accuracy of any ammunition, factory or reloaded, is the Hornady Lock-N-Load Concentricity Tool ($120). This tool allows you to measure the loaded round runout of any loaded round of ammunition. It also allows you to locate the high point of the runout and adjust it to nearly zero. I have taken factory ammunition and straightened it with this tool and improved my ammunition accuracy upwards of a half minute-of-angle (MOA), depending on how bad the runout was initially. When using this tool, you can usually get the runout down to .001 inch to .002 inch. At this level, other issues will likely cover up the runout from an accuracy standpoint. Runout of greater than .004 inch to .005 inch should be adjusted to a lesser amount.
One other simple tool I have found to be useful is the Hornady Lock-N-Load Comparator gauge set ($32). These handy tools allow you to perform your own quality checks on bullets. You can use them to measure from the base of the bullet to a contact point on the ogive. This measurement should be consistent in a quality bullet, certainly no more than .005-inch variation maximum across a box of bullets.
Comparator gauges can also be used to measure the distance from the base of the cartridge case to the contact point on the ogive of the bullet in a loaded round of ammunition. This dimension should be kept to a very small variation, less than .005 inch. If this measurement varies more than .010 inch, the performance of the ammunition will start to vary. This is because of the varying jump of the bullet to the rifling, and is where consistent hardness necks and consistent headspace cases make a significant difference. If the necks vary in hardness and some bullets seat harder than others, you hardly ever get a consistent dimension to the bullet ogive contact point. You either distort the ogive of the bullet more or less, or are pushing on the neck more or less and slightly changing the headspace.
If you are after the highest possible accuracy and performance consistency from your ammunition, there are many tools and tricks available that will allow you to achieve this. An important point to remember that overshadows everything you do is to try to get the straightest possible case and loaded round of ammunition that you can make. There are many specialized tools available from reloading tool suppliers beyond the basics that will aid you in achieving this.
In this column, I have primarily referenced Hornady’s tools simply because I worked for that company and they are what I am most familiar with. These are not the only good products available. Part of the fun of reloading is shopping and researching about the products on the market and making the best choice for you. In this quest, the internet and manufacturer websites are invaluable. So, jump in! Take your reloading to the next level.
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