Case Prep: Is it Really Necessary?
This article answers a common question among new reloaders: Is case prep necessary? We’ll cover what case prep involves – including cleaning, sizing and trimming — and explain when it’s critical, when it’s optional, and how case prep can affect performance.
If you’re wondering what steps you can skip and which ones you shouldn’t, this guide will help you make informed decisions at the bench.
Getting Started with Case Prep
Reloading is like most things in life, you get out of it, what you put into it. For handloaders seeking the highest quality, accuracy and precision possible, the first step in the reloading process is case preparation. Even new brass will need some attention paid to it prior to loading. A little attention to detail and you can produce ammunition that outperforms factory loads. It takes a little effort but it is easy when you have the right tools for the job.
Cleaning
Once brass has been fired, it will need to be cleaned. We recommend cleaning cases prior to resizing. This will ensure you get many years of use from your dies without scratching up the inside of the die. Running dirty cases through your dies can cause quality issues over the long run There are 2 types of cleaning processes, wet and dry.
Wet Cleaning
Brass can be cleaned in a wet solution using either our RCBS Rotary Case Cleaner or one of our RCBS Ultrasonic case cleaners. Both types use an RCBS Case Cleaning Solution mixed with water. The rotary style cleaner will also use stainless steel pins to help with the cleaning process. The rotary style cleaner will clean cases in about 20 minutes. The ultrasonic cleaner uses ultrasonic vibrations to help clean cases. Unlike the rotary cleaner, the ultrasonic cleaner does not use stainless-steel pins.
One advantage of ultrasonic cleaners is that they can be used to clean more than just brass. Using our RCBS weapons cleaning solution you can easily clean firearm parts like a bolt carrier group, muzzle brake or pistol slide. They can even be used to clean suppressors. Brass will need to be dried thoroughly after using either of these methods.
Dry Cleaning
The other method of cleaning your cases before resizing them is done with our RCBS Vibratory Case polisher using dry Case Cleaning Media and RCBS Polishing compound. Wet cleaning will get the case clean and is all you need, but if you want the ultimate shine that matches new factory ammunition this is how it is achieved.
sizing
Fired brass must be resized with either a full-length sizing die or a neck-sizing die. We recommend running factory new brass through a sizing process as well to ensure consistency. If you are reloading a bottle necked cartridge you will need to lube the case first.
- Lube may be sprayed on, rolled on using a lube pad, or applied via a lube die. And remember, a little goes a long way.
- Too much lube can cause hydraulic case dents while too little can result in a stuck case.
- You should be able to feel through the handle of the press if excess force is required to size if the case is not lubricated well enough.
- Straight walled pistol ammunition may not need to be lubed if being used with a carbide resizing die.
- For a full article on case lubrication how to, dos and don’ts, check out our other articles.
Case Trimming
When a cartridge is fired, it will expand to fill out the exterior dimensions of your firearm’s chamber. This will cause the brass to expand and stretch. During the resizing process the case is sized back down which will also induce stretching or lengthening of the cartridge case.
It is very important not to let brass exceed maximum length dimensions. A case that is too long may protrude into the throat section of the chamber which will force the brass into the bullet creating a higher chamber pressure. How do you ensure your brass stays within specification? Time to trim.
Most reloading manuals will list the trim length and maximum length allowed for the brass casing. Most rifle and revolver rounds will have a .010 tolerance. Pistol rounds such as 9MM Luger or 45 ACP which headspace off the case mouth, will typically have a .005 tolerance. If all your brass fits within these specs you may not need to trim. If you are crimping the rounds, it is essential that all cases be the same length to achieve a uniform crimp. All straight walled ammunition should be crimped as well as bottle necked cartridges when used in semi autos or with tubular magazines.
Trimming can be done with our RCBS Trim Pro 2 manual case trimmer or with some motorized help from the Trim Pro power case trimmer. Both styles of trimmers come with caliber-specific pilots to help you trim to the right length. Traditional trimmers require chamfering and deburring after trimming, but RCBS has a Trim Pro 3 way cutter head which will perform all these steps in one process.
Some handloaders elect not to bother trimming their brass, instead tossing their cases once they grow too far out of spec. While this is an option, it reduces the amount of firings you can get and brings you back to square one with new, or once-fired brass.
Keep track of the number of firings your brass has gone through by labeling your storage containers or bins, to ensure your brass is consistent.
Deburr and Chamfer
Deburring your cases is intended to simply debur – removing small, sharp pieces of brass – around the edges of the case mouth. We are not looking to remove a lot of material here or trim the case. We just want to give the bullet a smooth, burr-free mouth to get started into during the bullet seating operation. Chamfering, to be done after deburring, ensures there are no burrs on the outside of the case neck for reliable chambering by putting a small bevel or angle on the outside rim of the case mouth. While not completely necessary, precision shooters may choose to deburr flash holes in addition. Deburring flash holes uniforms primer flash into the case. This improves consistency in powder ignition which helps lower extreme velocity spread, one of many reasons handloaded ammunition outperforms factory ammunition.
Deburring and chamfer can be done with one of our handheld deburring tools or with the help of our powered RCBS Brass Boss. RCBS also offers a VLD (very low drag) deburring tool specifically for use with modern, long and sleek high BC bullets commonly used for match shooting or even hunting. You can also deburr your flash holes by hand with our caliber-specific RCBS tool.
If you’re trimming your cases, this step is a must.
Primer Pockets
Primer pockets will have residue left behind after firing that needs to be removed to properly seat the new primer. Wet cleaning usually does a pretty good job of removing this but you may need to physically remove any residue by using a Primer pocket brush attached to an accessory handle or this can be done faster with the RCBS Brass Boss.
Military Cases
Military ammunition calls for the primer to be crimped in place. Crimping of primers is not something done on most commercial ammunition or by reloaders. Crimping of the primers leaves a ring around the primer pocket which must be removed to seat a new primer. Much of the bulk ball type ammo sold in 223/5.56 , 9mm and 308/7.62×51 will have crimped primer pockets. There are two methods of removing the crimp from these cases, swaging and reaming. Swaging which can be done on your press with the RCBS Primer Pocket Swager or with the RCBS bench mounted Primer Pocket Swager Tool. The other method is reaming the pocket which cuts the metal from the pocket using the RCBS Trim Mate Military Crimp Remover in conjunction with the RCBS Brass Boss.
Conclusion
With case preparation, there’s lot of ways to get the job done. The quality and accuracy you expect from your reloaded ammunition will help guide you to the right process and equipment for you. Try and test different methods of case prep to see which tools and processes make a difference.
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