A lot of guys write in to Ask The Gun Editor and a good many of them are handloaders wanting to know the “best” load for their favourite cartridge. The vast majority of these requests are for rifle calibres, then handgun loading data, but very few ask for for shotgun loads. This is hardly surprising because there is hardly any need for load development with shotshells. All the shotshell reloader has to do is follow the recommended loads listed in various guides, and take care to match the components listed therein to duplicate the performance of factory loads.
Reloaders of handgun ammunition in this country are primarily concerned with finding a load that delivers good accuracy and functions reliably. These pistoleros shoot off many thousands of reloads every year at targets. Data for handgun cartridges is easy to come by and competition shooters seldom stray far from a combination of components that has been successful for them over a period of time.
Riflemen are entirely different. Most who write in are hunters and economy is not their major concern. They are more interested in gaining pin-point accuracy, the highest velocity with the flattest trajectory, and the highest retained energy downrange. If they’re trophy hunters they’ll want a load with enough punch to stop a charging lion or buffalo in their tracks. All of this sounds like a big ask, but it really isn’t. A well developed handload can be a spectacular performer for just about every purpose from vapourising varmints and dropping big-game at long range, to stopping dangerous game at close quarters.
Back in 1950 when I started handloading, it was universally recognized that in virtually all respects a carefully assembled handload was superior to a factory-loaded round. Not only was accuracy significantly better with handloads, but quite often it was possible to increase velocity by 100 fps without exceeding safe pressures.
An experienced handloader, for example, could load the 7mm Mauser so that it came close to equalling the performance of the popular .270 Winchester. High-quality bullets also assured the handloader of increased performance on game, and the experimenter had a wide range of bullets to experiment with in his search for the ultimate load.
Today the handloader finds it difficult to equal, let alone surpass the performance of factory-loaded ammunition, particularly stuff like Winchester Supreme and other top end loads for the simple reason that factory cartridges have to a greater degree surpassed the average handload! Now many calibres are now being loaded with premium controlled-expansion bullets or sleek spitzer boattails that were once the exclusive domain of the handloader, and ammo makers have refined their powder charges. But although ammomakers have lifted their game, one advantage they can’t match is being able to develop the one load that performs best in your rifle.
The burning question of course is, how do you go about finding your best load?
Actually, it is not quite as difficult as you might think. Let’s say you have a .270 Winchester rifle and that you want to work up a big-game load using 150-grain bullets. You refer to your reloading manual, but find that it lists thirty loads, using ten different powders, for the .270 with three different 150gn bullets. Don’t panic thinking you have to buy all ten types of powders and try all those different loads in order to find the combination that works best in your individual rifle.
Fortunately, you don’t have to try every possible combination because the solution to finding the best load is right there in your manual. Before you get started, however, there are a few things you should know about reloading manuals. Firstly, it is important to use a current manual. If your manual is many years old, you may miss out on some of the best loads using some excellent powders that have been introduced in recent years. Another reason for updating your manual is that loading data is often revised in the interest of safety and better performance, so that an efficient load you worked up a decade ago may no longer perform as well as it used to. Nor would it be unusual for what was some handloader’s effective long-range load years ago to start showing signs of excessive pressure.
If you are reloading for a number of different calibres, it’s probably a good idea to invest in a few different reloading manuals as well as any data put out by bullet and propellant manufacturers. This is because you will find considerable differences in maximum charges and/or their velocities. These conflicting numbers may be confusing, but are all valid because differences in guns, components, test equipment, testing procedures and operators will cause variations in results and thus in the published data.
Some of the loading data furnished by propellent and bullet makers is developed in special test guns having a universal reeciver fitted with special pressure barrels of minimum bore and groove dimensions - that are usually 650mm long and used to measure pressures as well as velocities.
Loading data in some manuals, Nosler’s in particular, is mostly developed using such ballistic laboratory equipment, but some others develop their data using standard hunting rifles. The Hornady manual lists .270 loads worked up in a Model 70 with 600mm barrel, and Speer used a Ruger Model 77 MK II. The 6th Edition Nosler manual shows .270 loads taken in a 600mm Shilen test barrel, while the Sierra data was developed in
a Savage Model 116 with 650mm barrel. Depending upon the manual, loads for other calibres have been developed using a variety of rifles and barrel lengths. The advantage of having several manuals on hand means you can select loads developed in a rifle similar to yours or at least one with the same barrel length. There’s no guarantee, however, muzzle velocities will be then same in your gun.
Most handloaders will choose the manual loads that give the highest velocities. This doesn’t mean that you should start with the listed maximum loads, but the high velocity loads do indicate which propellant or propellants are most efficient in a given cartridge and bullet weight. This matching of the powder to the capacity of the case and the weight of the bullet is critical to obtaining the optimum ballistic performance and accuracy.
When you check powder charges for the .270 Winchester in the manuals, you will notice that the heaviest charges of powder are the ones that give the highest velocity. This is because the .270 case has a large capacity for its bore size and thus is best suited by slow burning powders. But there’s a limit to how slow!
It is possible to use an ultra-slow powder that burns too slowly for this particular cartridge and bullet weight; which results in a heavier charge that fills the case to the mouth, but which generates lower velocity. On the other end of the equation, a faster-burning powder that only half fills the case may generate pressure at too fast a rate without giving as much velocity. The reality is, there are at least four powders available with burning charactistics that are well suited in the .270 Winchester with 150gn bullets - Re-19, Re-22, AR2213sc and AR2217.
Be aware that changing bullet weights for a particular cartridge can make it necessary to use propellants with different burning rates. An example of this is the propellants used for the highest velocities with light 90, 100 and 110gn bullets in the .270 - AR2209 and WIN-760 - which are rated as being slow - burning, but which are not all that slow.
Your manuals may show identical or similar velocities for widely different charges of two or more different powders. This may tempt you into choosing the load that requires less powder, thinking you’ll get more bang for your buck.
You may indeed save a little money, but pay a penalty by sacrificing accuracy. It is generally accepted that a rifle cartridge is most efficient and most accurate when the case is charged with a powder that nearly fills the case, leaving little or no air space. This is why you should always choose the powder in your manual that yields the highest velocity (efficiency) and has the highest loading density (accuracy).
The term “loading density) describes the percentage volume of a cartridge case that is filled by the propellant. There are methods of calculating loading density, but if a powder charge fills a case up to the base of the bullet, that load is rated as being 100-percent. Obviously, if the case is less than full, the loading density is listed in smaller percentages. As far as I am aware, the only loading manual that lists “Load Density Volume is Nosler’s, now in the 6th edition. This immediately gives you an indication of how fully a particular charge will fill the cartridge case.
Some handloaders are shocked to find that some loads listed in various manuals will overflow the case. Their first thought is that they’ve adjusted their powder measure wrong, but when they weigh the charge and find that it matches the load in the manual, they are puzzled. It is quite logical for them to assume that the guy who wrote the manual made a blunder.
In fact, there are a good many listed loads - including some of the best and most accurate - that more than fill the case. The trick is in knowing how to get the powder into the case. If the charge fills the case nearly
to the top, you can settle the powder by holding a finger over the case’s mouth and gently tapping it on the bench. But an easier way to get a lot of powder into the case is to use a funnel with long drop tube. You’ll be amazed at how densely the powder granules will pack down into the case when you use a 10cm drop tube accompanied by a little tapping. High density loads tend to ignite and burn uniformly which makes them more accurate than reloads which have the charge loose in the case.
Despite being dropped through a long tube, some powder charges may still fill the case to its mouth, resulting in what is known as a compressed charge. These most commonly occur with magnum cartridges using heavy charges of slow-burning coarse- grained stick powders. Today, we have modern powders like AR2213sc (short cut) which have finer granules and require less compression.
Some handloaders are scared of compressed loads, but within limits their concern is misplaced. A charge that fills the case up into the neck and is compressed by the bullet is as safe as any other. If your manual lists such a load, and you are using the same bullet weight, powder charge and brand of case,
you can be sure that the load is safe.
But bear in mind that cartridge cases of different makes can vary considerably in capacity, even if the calibre is the same.
A charge that might fit easily in, say a Winchester case might overflow in a Remington or Federal case, or vice versa. This is a compelling reason why you should never start off with a maximum charge. Always begin with the starting load listed in your manual and work up in small increments. If bolt lift is easy and fired cases give easy extraction, gradually increase the load to the full recommended charge, that is if you want top velocity. And don’t be surprised if the fastest load is the most accurate. This isn’t a coincidence but rather the result of a well-balanced load that is just right for your rifle. When a rifle doesn’t shoot well with top loads, but is significantly more accurate with slightly reduced loads, it is often an indication that there is something wrong with the rifle, the ammunition or the shooter’s technique.
When testing your rifle and reloads for accuracy, it is a mistake to try too many different combinations of propellants and charge weights - unless you’ve got a lot of time on your hands. I’ve known handloaders who load five rounds each of a dozen or two dozen different load combinations and then shoot groups with them all. They single out the smallest group and declare it the “best” load on the basis of just one group. This is, of course, a worthless estimate.
It is a lot more meaningful to test fewer load combinations and take larger samplings. Fire at least four five-shot groups with each load. The more groups you fire,the more reliable your results will be. To make a genuine appraisal of your rifle’s accuracy potential, throw out the best group and the worst one, and average the rest. That will give a more realistic idea of the true accuracy of your rifle.
The methods described here are a simple but reliable way to discover the best loads for your rifle just as long as you’ve taken care to prepare your brass properly, match components, choose the best powder and use the optimum bullet-seating depth for your rifle. Failure to do this will invalidate the results of your testing.
This article was first published in Sporting Shooter, March 2012
The NSW Game Council will get a funding boost of $1.7 million to $4.35 million in the 2013/14 state budget.