What is a Full Length Resizing Die?
Definition and Function
At its core, a full length resizing die is a precision-engineered tool used in the reloading process to restore fired brass cartridge cases to their original dimensions, or at least close to it, as specified by SAAMI (Sporting Arms and Ammunition Manufacturers’ Institute) specifications. Think of it as a shaping tool that puts a fired case back into a shape that will safely and reliably feed into your firearm’s chamber.
Unlike neck sizing dies, which primarily work on the neck of the cartridge case, a full length resizing die affects the entire case body. This means it returns the case to the factory specifications, including the shoulder, body diameter, and even the overall length. The process involves forcing the fired brass through a hardened steel or carbide die, which gently squeezes and reshapes the case. Inside the die, there’s also a mechanism for removing the spent primer, essential for preparing the case for a new primer.
Physical Components
The physical components of a full length resizing die typically include the die body itself, which houses the other working parts. Inside the die body, you will usually find an expander ball (or expander mandrel). This small component sits in line with the decapping pin (which knocks out the spent primer) and will resize the inside of the case neck to receive the bullet. The die is threaded to allow you to precisely adjust it within your reloading press.
The Resizing Process
When a case is fired, it expands to fill the chamber of the firearm. A full length resizing die reverses this expansion. As the case is pushed through the die, the body of the brass is brought back to its original or slightly smaller size. This is crucial for ensuring consistent chambering in your firearm, which leads to increased accuracy and improved reliability. The decapping pin, situated within the die, also removes the spent primer, preparing the case for the next round of reloading.
Why Use a Full Length Resizing Die?
Benefits for Reloaders
The benefits of using a full length resizing die are numerous, particularly for reloaders seeking consistent performance and dependable functionality.
First and foremost, it ensures consistent cartridge dimensions. By bringing the case back to standardized measurements, the full length resizing die guarantees that the cartridge will fit properly in the chamber of your firearm. Consistency is key to achieving tight shot groups.
Chambering Reliability
Chambering reliability is a significant advantage, especially in firearms that rely on consistent feeding. This is particularly important for semi-automatic rifles and lever-action rifles, where smooth and reliable feeding is essential for proper function. A full length resizing die helps to eliminate potential feeding issues by restoring the case to the correct dimensions.
Addressing “Sticky Bolt” Issues
Another benefit is the ability to address the “sticky bolt” issue often caused by case expansion. When a case expands too much during firing, it can become difficult to extract, leading to a sticky or hard-to-open bolt. The full length resizing die combats this by bringing the case dimensions back to specifications, ensuring smooth extraction and cycling.
Ideal for Mixed Brass
Furthermore, full length resizing dies are ideally suited for cases fired in different rifles. This is common if you share brass with fellow shooters. It’s also a great tool if you are unsure about the exact dimensions of the chamber of the rifle the brass originated from, especially if the source of the brass is unknown, such as when you’ve collected cases at a range. In these cases, a full length resizing die ensures that each case will fit properly in your firearm.
Overall Ammunition Performance
Ultimately, the consistent dimensions provided by a full length resizing die contribute to overall ammunition performance and accuracy. By standardizing the case dimensions, the die creates a solid foundation for consistent bullet seating, powder ignition, and ultimately, improved groups downrange.
When to Use a Full Length Resizing Die
Reloading for Multiple Firearms
Deciding when to use a full length resizing die depends on your specific reloading needs and the type of firearms you are reloading for.
One crucial scenario for its use is reloading ammunition for multiple firearms in the same caliber. If you plan to use the same ammunition in several rifles or handguns, full length resizing is essential to ensure that the cartridges will fit properly in all firearms. This is especially important if the chambers are slightly different.
For Semi-Automatic and Lever-Action Rifles
If you’re using semi-automatic rifles, full length resizing is almost always the preferred method. These firearms rely on reliable feeding and extraction, and the precision afforded by full length resizing is essential for ensuring consistent operation. Lever-action rifles also greatly benefit from this type of resizing, and the smooth cycling of the action.
Cases with Generous Chambers
Another good use is when the brass will be used in a gun that has a generous chamber, or one with a bit of play. If the brass is not resized back far enough, it might not chamber, or might be hard to chamber.
Hunting Applications
In the world of hunting, where reliability is of the utmost importance, full length resizing is highly recommended. The last thing a hunter wants is a malfunction in the field. And with this method, you can be sure that the ammunition is made with the proper case dimensions.
Troubleshooting Chambering Issues
If you’re experiencing difficulty chambering your resized cases after neck sizing, switching to a full length resizing die is usually the answer. It ensures that the case body is sized correctly to fit the chamber of your firearm.
Brass from Unknown Sources
It’s also the go-to method when using brass from unknown sources. By full length resizing the brass, you’re giving yourself the best chance of having consistent dimensions, regardless of the original firearm the brass was shot in.
Choosing the Right Full Length Resizing Die
Types of Full Length Resizing Dies
Selecting the right full length resizing die involves considering a few key factors.
There are a few different types of full length resizing dies available. Standard dies are the most common and are suitable for the vast majority of reloading applications. Small base dies, on the other hand, are specifically designed for semi-automatic rifles and other firearms that may have tighter chamber tolerances. The small base design resizes the base of the case slightly more than a standard die, ensuring reliable chambering. These dies are not always needed, but in some cases, they can improve reliability, especially with cases known for expansion issues.
Carbide Dies
Another option is to choose dies made of tungsten carbide. These dies offer an exceptionally hard, slick surface that reduces friction during the resizing process, which can extend the life of your cases. Often, you do not need to apply a case lubricant when you’re using carbide dies.
Manufacturers and Features
Consider the manufacturer. Reputable brands, such as RCBS, Redding, Lee, and Hornady, consistently deliver high-quality dies. These companies offer a diverse range of dies, each designed to provide precision and dependability. Research the specific features of the die you are interested in, like the expander ball, and decide if this feature will fit your needs.
Using a Full Length Resizing Die – Step-by-Step Guide
Equipment Needed
The reloading process can appear complex to the uninitiated, but it is well within the reach of any dedicated shooter. By following a step-by-step process, you can quickly learn the fundamentals.
Before you start, you will need the following equipment: your reloading press, a shell holder that fits the caliber of your brass, case lubricant, a case trimmer (for potentially trimming cases) and a chamfering tool.
Preparing the Cases
Begin by thoroughly inspecting your fired cases. Clean them to remove any dirt, debris, or residue. This also gives you the opportunity to visually inspect the case for any damage, such as cracks, dents, or other signs of wear.
Lubrication is Key
The correct case lubricant is critical for the success of the full length resizing process. Without it, cases can stick in the die and be very difficult to remove, and in extreme cases, you can damage the die or the case itself. Apply the lubricant evenly to the exterior of the case. Some common methods include spray-on lubricants, gel lubricants, or using a case lube pad. Make sure to lubricate all the way to the case shoulder, especially with bottle-necked cases.
Setting Up the Press
Next, insert the shell holder into your reloading press. Then, screw the full length resizing die into the press until it touches the shell holder. Once you’ve set up your reloading press, you can begin the resizing process.
The Resizing Process
As the case travels upward into the die, the die will compress and resize the case. At the same time, the decapping pin, located inside the die, will push out the spent primer.
Checking for Consistency
After resizing, check your cases for consistency. They should look uniform and have the correct dimensions. A case gauge is a useful tool for checking your resized cases.
Trimming and Chamfering
If necessary, trim the cases to the proper length. Over time, brass expands slightly when fired, which can cause the overall length of the case to increase. This is especially true if you are using a lot of full power loads. Finally, you will want to chamfer and deburr the case mouth.
Troubleshooting Common Problems
Stuck Cases
Even experienced reloaders can run into problems. Here are some common issues and their solutions.
If a case sticks in the die, the most likely culprit is insufficient case lubrication. Double-check that you’ve applied enough lubricant and that it’s evenly distributed across the case. It’s also possible that the die itself is not clean.
Chambering Issues
If you are finding that the resized cartridges are difficult to chamber in your firearm, the die may be adjusted incorrectly. Ensure that the die is screwed down far enough to properly size the case. If this is still occurring, you might be bumping the shoulder back too much, which can interfere with chambering.
Maintaining Your Full Length Resizing Die
Cleaning
To ensure longevity and optimal performance, proper maintenance is essential.
After each reloading session, clean your dies to remove any built-up residue. Most reloading die manufacturers sell cleaning solvents specifically designed for the task. You can also use a soft cloth or brush to clean the internal components.
Storage
Store your dies in a clean, dry location away from extreme temperatures. When storing your dies, consider reassembling them and placing them in a die box for safekeeping.
Inspection
Periodically inspect your dies for wear and tear. Over time, the die can become worn or damaged. If you notice any signs of wear, such as scratches or burrs, consider replacing the die.
Conclusion
The full length resizing die is a cornerstone of the reloading process, providing reloaders with the ability to craft ammunition that is as accurate and reliable as it is customized. By understanding the function of these dies, learning how to use them correctly, and practicing diligent maintenance, reloaders of all levels can harness the full potential of this vital tool.
The key is consistency. Remember to prioritize the quality of your components, use precise measurements, and follow proper procedures. The results will speak for themselves.
Continue experimenting and refining your reloading practices. The more you delve into the art of reloading, the more you will appreciate the role of the full length resizing die in achieving exceptional accuracy and reliable performance. Keep refining, and you will find that your results in the field are as dependable as the tools you use.
