When you decide to take your rifle shooting to the next level and improve your accuracy and precision, whether just for your own pleasure, to compete in precision rifle shooting matches or just to increase your hunting accuracy, there comes a time where you will need to do rifle load development.
What is load development? Load development is when you get the variables in a loaded cartridge to a specific set of specifications to match your rifle the best. Every single rifle, whether it is a factory rifle with factory barrel and chamber, or custom rifle with custom reamed chamber and barrel, shoots differently than another. So although most factory ammunition will shoot sufficiently well out of most rifles, it is only when you start focusing on shooting sub-MOA or sub half-MOA regularly, that you will notice that generally factory ammunition does not deliver the precision you require, and load development becomes necessary.
Yes you can pay someone else to do load development for you, but not only will it work out cheaper to do it yourself in the long run, you also learn so much about the dynamics of rifle shooting, cartridge composition, bullet propulsion and bullet ballistics, during the load development and reloading process that it automatically improves your precision shooting, and concept application. Would you really want to give away that improvement opportunity to in your quest for precision and accuracy?
Often people think just about getting the smallest group for their rifle, this is however not actually the main goal, the main goal is the get the smallest group that you can consistently shoot out of a rifle in differing weather environments, and with small margins of error whilst reloading.
Load Development Methods
There are three main load development methods, each having it’s own end goal which you have to focus on to get a load recipe developed for the specific rifle. These three are the Optimal Barrel Time (OBT) method, the Optimal Charge Weight (OCW) method, and the Ladder Test Method, also often called the Sweet Spot Method or the Ladder method. Which you decide to follow or make use of, will depend on your personal preference and equipment at your disposal, however there have been successful champion shooters in each discipline of precision rifle shooting, making use of each of these load development methods, so there is no real right answer as to which one is the best, and each of those methods are sufficient to develop an accurate cartridge for a rifle, if done correctly.
Optimal Barrel Time
The OBT method, involves getting the exact parameters of your rifle, and the different components of the cartridge, inputting them into ballistic software or a ballistic program like the paid QuickLoad or the free Gordon’s Reloading Tools after having shot that cartridge and getting the muzzle velocity (MV) of the bullet with those specifications shot out of that rifle, and then the software will calculate the barrel whip or barrel resonating and barrel harmonics after a shot is fired and the bullet travels through the barrel, to ultimately determine the nodes for that rifle with that cartridge. You then adjust the powder charge up or down as to reach the nodes that the software tells you, it is as simple as that.
What are the nodes? A node is the points in the resonating pattern that the barrel travels in, where it is at the center point again. You want the bullet to leave the barrel at this point, as it will provide the most consistent flight path and point of impact(POI) shot after shot, in theory.
This method is ideal for shooters who like to get super technical with details and do not mind learning a new computer program or working on a computer, and have access to a computer. The instructions to work the programs are easy enough for any adult to learn. Personally we prefer Gordon’s Reloading Tool as it is free, and it seems to be a little more precise even providing half nodes and not only full nodes.
Optimal Charge Weight
What is the optimal charge weight method of load development, how to find optimal charge weight, and how to read the OCW test?
The OCW load development method, involves shooting an optimal charge weight test, consisting of shooting different increments of powder charge, with the same cartridge components, groups of three or five shots for each increment, and then comparing them all to one another, to find the most central, average point of impact between them all.
The point of this, is to determine which gunpowder charge weight, provides the most consistent point of impact, even if external factors like the weather or slight errors in the loading of the cartridges vary slightly. So if there is a slight margin of error, the shots will still impact closely to the point of aim. Thereafter playing with the jump to close the groups down more tightly.
This OCW load development method focuses on minimizing variation in point of impact for various margins of error.
Ladder Test Method / Sweet Spot Method
What is the ladder test method?
The ladder test method of load development, or also as it is often know the sweet spot method of load development, is a more practical method, where a string (or ladder) of shots are shot at 300 yards, with cartridges loaded at 0.1 or 0.2 grain increments, just one of each, and then determining which of them are sweet spots.
What is a sweet spot in load development?
A sweet spot, is similar to a node, it is found where two or three consecutive shots, in differing but following increments, are at roughly the same speed or sit roughly on the same horizontal plane as one another, often both of these together. Then you load the middle powder charge weight in one of those sweet spots.
The reason you are looking for these sweet spots, and why you want to load your cartridges within one of these sweet spots, is because it shows that if slight variations or errors in powder charge are made either up or down, it will still shoot roughly at the same velocity and have roughly the same point of impact. This will also hold true for variations in environmental factors, like temperature and pressure, either up or down. This consistency is what translates into precision during shooting.
This method is popular because it does not require the use of computer software, and when done properly, is also the most efficient on ammo use, as one can find a load or sweet spot or two, often within the first ladder of 12 or more cartridges. This method was pioneered and made famous originally by a Frenchman named Creighton Audette.
One point to remember with this method though, is that you have to be able to differentiate between every single shot, in it’s correct sequence, with it’s corresponding velocity, so this is either done through the use of equipment like the long shot camera when alone, or by having a friend near the target behind a safe mound or wall with a radio that you can signal after each shot to mark it for you. You cannot go up to the target to mark it yourself after every shot, as you want to fire the shots as soon as possible after one another to ensure constant similar conditions for each shot.
One piece of equipment, all of these methods rely on, and is therefore a MUST HAVE for load development, is a chronograph. As without the actual velocity shot from the specific rifle, it’s ballistic data and reactions to changes in cartridge variables cannot be determined.
For the OBT method to be used effectively, the correct parameters of both cartridge and rifle need to be input into the software. The caliper will be used to measure the cartridge overall length (COAL) as well as the case length.
Once COAL has been measured, use a comparator to see what the base to ogive measurement is, and keep working with that, as it is much more accurate, easy and consistent means of measuring cartridges, especially ballistic tipped bullets.
An overall length gauge is used to measure the maximum overall length (OAL) cartridge that your rifle can take, and then you can determine the length of the cartridges you want to load with. The preferred starting jump would be 0.020 inches. Once you have developed your load and all other variables, you can start playing with this jump to see if groups open up or become tighter.
Syringe with Needle
Another important parameter that needs to be measured and input into the reloading and ballistic software during load development, is the H2O case volume of a case that has been fired in that specific rifle. The best method of measuring that, would be to place the fired case, with primer in it, on top of an electronic scale, zero the scale, and then start adding water to the case until the water level at the top is exactly in line with the rim of the case mouth. A normal injection syringe with needle is the easiest and most precise way to add water to the case in small adjustments to get the level exact. This measure volume of water is then used in the case volume parameter.
Now that you have successfully developed a load your rifle shoots well with, follow the advanced reloading for precision rifle guide to keep loading consistently precise cartridges in this load.
Good luck, and as always, enjoy the process.
John M. Jerkins says
May I suggest a correction to this article?
Paragraph header: Syringe with Needle
Line 5 “level at the top is exactly in line with the rim of the case.”
I think it would be more clear if the word “mouth” was added after the word “case” at the end of the sentence.
Otherwise confusion arises as the “case rim” is generally the location one measures to obtain “rim diameter” at the end opposite of the “case mouth”.
Thanks for the article!
I’ve started reloading in 1972 with the .243 Winchester.
Thank you for the suggestion, correction was made.