Developing Accurate Hunting Handloads
Date: Jul 31 2013
The benefits of handloading ammunition are many, but primarily include savings, accuracy improvements (through tailoring loads to a specific rifle or hunting application), and sometimes velocity can be safely enhanced over factory loads. It is also fun. In visiting with many dedicated big game hunters regarding their handloaded ammunition, there remain concerns about reliability and proper performance. Perhaps a cartridge will fail to perform when pointed at the trophy of a lifetime or, worse, when facing dangerous game a few steps away, wherein a mistake has the potential to cost life or limb. Thus factory loads are often chosen.
Most U.S. manufactured ammunition is within industry (SAAMI) specifications, which include case minimum and maximum diameter and length, bullet diameter, overall cartridge length, maximum average pressure limits, etc. These specifications are important to maintain so cartridges feed, function and chamber reliably in all sporting arms. Maximum pressure limits are established to prevent cases from rupturing, primers blowing, sticky extraction or perhaps even damaging guns. Handloaded ammunition should generally be assembled to similar specifications, but it can be tailored to a specific rifle; however, doing so may make it unsuitable for another rifle of the same caliber. And certain older cartridges can be ballistically improved when they are chambered in modern rifles that are stronger, rather than early guns in the same caliber. Examples include 6.5mm Swedish Mauser, 7x57mm Mauser, .45-70 and others.
Case selection is paramount. It is best to start with new, unfired cases for hunting ammunition; however, cases that have only been fired once or twice can also work. Cases that have been fired and reloaded many times should be used for practice or varmint shoots, as the chance of some form of failure increases. Regardless, all cases should be inspected for factory defects (yes, they do exist in new cases), as well as cracked necks, possible case separation of previously fired cases, a damaged extractor groove, rims, etc. Used cases should be sized in either a full-length or small-base sizer die so they will chamber easily, while new cases should be partially sized to true up the neck and case mouth, which will aid in obtaining proper bullet tension. An option that I heartily suggest is NoslerCustom brass that starts as high-quality cases but is factory tuned with flash holes deburred, primer pockets uniformed, sized, case mouths chamfered and is ready to load.
Some may choose to only neck size cases. While this might offer slight accuracy advantages and longer case life, loaded cartridges will fit snugly when the action is closed, which can be a problem under some hunting circumstances where working the action fast may be important. This approach is fine for select varmint rifles but should generally be avoided for hunting large or dangerous game.
Occasionally meticulous handloaders follow the lead of benchrest shooters and turn case necks to obtain additional uniformity and accuracy. This is a proven step when used in match chambers with minimum or custom dimensions, but the chambers of most sporting rifles are much more generous; this step is usually counterproductive, and one that I avoid.
After cases are sized, they should be checked for correct overall length. If they are too long, they can be difficult to chamber, and pressures may increase and thus should be trimmed to industry standard lengths, then chamfered outside and inside (with the latter aiding in bullet seating). Other case preparation steps to consider include flashhole deburring and primer pocket uniforming.
Choosing the correct primer and priming processes is often overlooked, but they are important to the reliability of handloads. Handload data is usually developed with a specific primer, and it is generally best to use the same primer types that are used in factory loads so that pressures are similar. For example, the .30-06 is loaded with large rifle primers, and using large rifle magnum versions will increase pressure and often decrease accuracy.
The priming process is important to reliability. I prefer hand-held priming tools, but there are benchmounted tools and others that are excellent in every respect. Most tools require that primers be dumped into a tray, then tipped anvil up (and either inserted into a tube or fed into the tool). At this point, they should be inspected for uniformity and quality before priming cases. After handloading around a million rounds, give or take, I have found substandard primers.
Primers should be seated so that the anvil is fully in contact with the bottom of the primer pocket. Thus seated, industry specifications indicate that the primer will be between .002 to .005 inch below flush. A primer that is seated “high” may not allow cartridges to feed correctly, and they might even cause misfires, as the firing pin blow usually has to finish “seating” the primer, which effectively cushions ignition. A primer that is seated too deeply can likewise cause misfires, as it is too distant from the firing pin.
Choosing a powder is not always easy. Extruded powders have been popular for many decades in common hunting cartridges, and they work very well, offering accuracy and top velocities. However, many of them feature long log shapes that make them difficult to throw from a powder measure, and weighing each charge is sometimes necessary, which is something of a slow process. Some variations have been shortened to permit improved metering. The accuracy and velocities offered by modern spherical powders make them likewise excellent choices, and they meter with extreme uniformity, which eliminates the need to weigh each charge so they can be thrown with speed and accuracy.
Always use credible load data, and avoid loads that are showing signs of excess pressure, sticky case extraction, blown primers, etc. They may appear promising, as they offer a slight ballistic advantage over factory loads, but beware, as they might prove less than perfect in reliability. Hunters must have maximum reliability. Loads showing signs of excess pressure will eventually prove less than perfect by leaving a primer in the action (tying up the gun), rupturing a case or sticking a case, usually at the worst possible moment. If maximum loads are reduced just 50 or 100 fps, this will usually drop pressure enough to obtain reliability under all weather conditions, including extreme heat and cold. With more than 170 canister grade powders currently available, I am unaware of any cartridge that cannot have its ballistics duplicated through handloading, while staying within prescribed pressure limits.