Preparing Brass for Match Shooting

By Dr. Jim Clary


In a perfect world, new brass would slide right into the chambers of our target rifles without any preparation or modification. Unfortunately, that is not the case. Most competition rifles are custom made. As such, different reamers are used for the chambers of the same caliber, which produce necks of varying diameters. In other words, for a caliber like the 6.5-284, chamber neck diameters can vary from 0.286” to 0.298”. Brass manufacturers produce a standard neck diameter of 0.296” for the 6.5-284. Hence, most competition shooters are required to modify the brass to fit their rifle.

Having briefly outlined one of the many reasons for case preparation in target shooting, the following steps are recommended to prepare your brass for competition. There is some disagreement among shooters as to the order of the steps. Some will state that additional steps are necessary. The bottom line is that there is no absolute “written in stone” rule for case preparation. The following procedures apply to most shooters and you as an individual may add an extra one along the way, or decide that one or more are unnecessary. These steps are basically the same ones recommended by well-known shooter and author, Jacob Gottfredson. There is no more knowledgeable person on the planet when it comes to preparing brass for precision shooting.

Step 1: Full-length resize the pieces to insure that they all have the same shoulder-body configuration. Redding dies are the best for this step, as their manufacturing tolerances are very exacting and they produce excellent results.

Step 2: Trim all cases to the same overall length. This ensures that the necks of each case grip the bullet in the same way. I find it amazing that the Forster case trimmer, manufactured more than forty years ago, still works best today. However, check to make sure that your cutter is sharp, and replace it if necessary. A sharp cutter in the Forster only produces a slight burr, while a dull one results in a pronounced burr. A dull cutter also requires more effort to trim the cases.

Step 3: Chamfer the necks. There is usually a burr around the neck as a result of case trimming. It needs to be removed before you use the expansion die in the next step. There are many good deburring tools on the market, including Sinclair, Forster, Redding and RCBS, all selling for less than $20.

Step 4: Expand the necks so that they all have the same diameter. Although this step is very simple with the expanders available, it is advisable that you purchase the same brand expander as neck turner. That insures that the mandrels are the same. For example, if you are going to use a K&M neck turner, pick up the K&M expansion die. If you like the Sinclair neck turner, buy the Sinclair expansion die. They are all supposed to be manufactured to the same specification, but there are differences in tolerances, so why take the chance. Make sure that you lube the mandrel each time, or the inside of the neck. Otherwise, you may get a stuck case. For this task, Imperial Sizing Wax is as good as it gets. You use this stuff very sparingly. It is also an excellent lubricant for the FL resizing stage.

A lot of shooters use the expander die on the necks before full-length resizing the cases (Step #1). The logic here is to insure uniform and concentric necks prior to sizing. I am not sure which is better, as I have done it both ways and not noticed any difference in the end result.

Step 5: Turn your necks to a uniform diameter and concentricity. There are significant differences between reloading for hunting and reloading for long range target shooting. Hunting rifles have fairly standardized chambers which will handle most all reloads without neck-turning. However, nearly all long range target rifles are custom made. As such, their chambers will vary from gunsmith to gunsmith. That is why we are required to neck-turn the brass. I will use the 6.5-284 as an example.

The “standard” neck diameter of the case as it comes from the factory is 0.296”. If you have a no-turn neck chamber in your gun of 0.297” to 0.298”, you simply FL resize the new brass with a 0.293” or 0.294” neck bushing in the die which will resize the neck to 0.293” or 0.294”, depending on which you used. The final loaded round will chamber easily and have the proper neck tension.

Bushings are only capable of “squeezing” the neck down two to three thousandths of an inch. If your chamber is cut to a 0.294” neck diameter, you have to turn the neck. The FL die (with bushing) will not size a factory neck of 0.296” down to 0.292” or 0.290”.

In our custom 6.5-284, the chamber is cut to a 0.294” neck. We neck-turn to 0.292” and then FL resize them with a 0.290” neck bushing in the die. Our loaded rounds measure 0.2925”, providing good neck tension on the bullet. The rule of thumb here is to turn your necks 0.002” below the chamber cut, and then order bushings at 0.002 and 0.003 below that: i.e., with a 0.292” turned neck you can use a 0.290” or 0.289 bushing.

Turning necks can only be described as a pain in the butt. I don’t know of anyone who looks forward to this phase of case preparation. You need a shell holder, a cordless drill and a K&M or Sinclair neck turning tool. Clamp the shell holder into the chuck of your cordless drill, turn it on to slow speed and move the cutter across the neck up to the shoulder. Do this a couple of times to insure a smooth cut, removing any ridges. Adjust the cutter on the tool in small increments to shave off a little at a time until you get the right depth.

I really hate turning necks. However, my wife found a way to make it easier. On one of our frequent trips to Harbor Freight, she spotted a mini metal lathe for $246. This was considerably cheaper than the powered neck-turning units on the market. This little beauty has a variable speed control, no belts and a chuck that holds our Sinclair shell holder perfectly. If you are going to be turning a lot of cases, check out this lathe. It saves a lot of time.

Step #6: Deburr the flash hole and use a primer pocket tool to “smooth” out the pocket. However, if you use Lapua or Norma brass, this step is usually unnecessary. That is how good their brass is. If you use cheaper brass, which shall remain unnamed, you must take care to remove the burrs from the flash holes and “clean” out the primer pockets to make them uniform for proper primer seating.

Step #7: Check the concentricity of your cases from the shoulder along the neck. My experience with Lapua brass is that this step is not necessary. However, if you are using Winchester or R-P brass you will probably have to buy a concentricity gauge and check all of your brass.

Step #8: Weigh all of your cases. Some shooters divide their cases into “lots” for loading and shooting. Most F-Class shooters weigh the cases to obtain cases to within +/- one grain in weight and discard the others. I don’t mean throw them away, just don’t use them. There are a lot of shooters that believe this isn’t necessary and they will be happy to take them off your hands. Or, you could chamber a hunting rifle in 6.5x284 and have all the brass you’ll ever need.

Step#9: Use a Redding Neck Sizing die with the proper bushing to neck size the brass for your chamber.

Step #10: You will now want to check the headspace. I recommend a Redding Instant Indicator Die to determine the head space in relation to the SAAMI length. This die allows you to correct and size your brass. This tool also lets you check the seating depth of the bullet as well as the uniformity of your bullet. This tool is a “must have” for all competition shooters.

Step #11: Square the heads with the base of the case. This is easily done with a Sinclair length trimmer.

There you have it. Your brass is ready to load and shoot. Of course, then you start all over again, which is part of the fun.




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Copyright 2008 by Dr. Jim Clary. All rights reserved.



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