Economy, increased accuracy, and improved performance are common motivations for hand loading cartridges. Reloading fired cases can save the shooter money and provide the shooter with more, and higher quality ammunition within budget. Reloading may not be cost effective for occasional shooters, as it takes time to recoup the cost of the equipment, but those who shoot on a regular basis will see benefit as the brass case (the most expensive component) can be reused many times (with proper maintenance). Besides economy, the ability to customize the performance of the ammunition is a common goal. Precision target shooters seek the best achievable accuracy, as well as the best shot-to-shot consistency.
There are three aspects to ballistics: internal ballistics, external ballistics, and terminal ballistics. Internal ballistics refers to things that happen inside the firearm during and after firing, but before the bullet leaves the muzzle. The hand-loading process can increase accuracy and precision through improved consistency of manufacture, by selecting the optimal bullet weight and design, and tailoring bullet velocity to the purpose. Each reloaded cartridge can have each component carefully matched to the rest of the cartridges in the batch. Brass cases can be matched by volume, weight, and concentricity, bullets by weight and design, powder charges by weight, type, case filling (amount of total usable case capacity filled by charge), and packing scheme (characteristics of granule packing).
In addition to these critical items, the equipment used to assemble the cartridge also has an effect on its uniformity/consistency and optimal shape/size. Dies used to size the cartridges can be matched to the chamber of a given rifle. Modern hand-loading equipment enables a rifle owner to tailor fresh ammunition to a specific firearm, and to precisely measured tolerances far exceeding the comparatively wide tolerances within which commercial ammunition manufacturers must operate. In the precision rifle community (visit Tacticalmatches to talk to some of the best precision shooters in the nation), a common topic is, “What is the best possible ammunition?” Some precision shooters emphasize that hand loads excel over the mass-manufactured precision rifle rounds. The following will help us to determine an answer to the question.
Hand load accuracy theory
Every rifle barrel develops some sort of harmonic vibrations when the cartridge is fired. A rifle barrel’s vibration can also be somewhat described as a three-dimensional wave or corkscrew movement, and is caused when the bullet is accelerated into a rapid spin caused by the rifling inside the barrel. This can be seen on high-speed film, and it is pretty impressive that we are able to hit anything with the amount of barrel movement present.
It is impossible to fully eliminate all barrel movement, even if the rifle has one of the thickest barrels in production. Even thick barrels will vibrate with every shot and any velocity variation will alter where the muzzle is finally located when the bullet exits. The random movement of the muzzle will give some sort of deviation and rise to increased group size, which is one of the reasons we see larger groups at distance.
The most experienced rifle builders will always allow the barrel to flex, given the idea that if the barrel’s movement cannot be eliminated, the next best solution is to have flex/harmonic consistency. Some of the best rifles in production have their actions and the first inch or so of the rear of the barrel bedded tightly into the stock to hold the receiver firmly, with the remainder of the barrel free-floated. In addition, short, thick barrels have wide(r) nodes, so velocity isn’t as critical to achieving a sweet spot.
Since the velocity of the bullet passing through the barrel affects the way it flexes, accurate loads should deliver as consistent a velocity from shot to shot as is possible so that the bullet exits the muzzle at the same point in the ‘flex’. You can control this to a certain degree, but is impossible to entirely eliminate shot-to-shot velocity deviation. At around a variation of 10 to 12 f/s, it may become almost impossible to reduce the effect any further.
It has long been understood that barrels perform best within certain velocity ranges. These velocity ranges are commonly referred to as a ‘harmonic nodes’ or ‘sweet spots’. The reason for this is that the tensile strength (or the ability to resist further bending) of the metal alloy increases as it moves further away from its static state. The barrel gets stiffer when it is forced to the extremity of its movement.
At the point of maximum movement, slight velocity variations change the muzzle location less; resulting in lower shot dispersion and thus a smaller group size. What most shooters don’t understand is that harmonic vibration is related to the mass of the bullet. Therefore, once the harmonic node(s) for a given weight bullet is identified, a lot can be learned, if you know the velocity.
There is also a new theory of ‘barrel timing’ being developed based upon data obtained from strain gauges. Upon firing, the chamber swells slightly and an annular ring of expansion travels down the barrel, causing the bore to expand slightly. This effect continues as the expansion reflects back and forth along the barrel, diminishing with each passage. Initial data suggest that not only should a load perform best at one of the velocity nodes, but that the bullet should not exit the muzzle at the same time that the expansion ring reaches the muzzle, as the slight increase in bore size adversely affects accuracy.
Load development, equipment, and the hand-load process
Precision rifle shooters covet ‘the perfect bullet’, seeking optimal performance and accuracy. In order for the shooter to get the type of accuracy they are looking for, they turn to load development.
Some of the top shooters in the nation practice hand loading and have seen some great results in return. Having the capability to precisely measure and examine every component within the hand loading process gives the shooter ‘hard data’, unlike some commercial rounds. Hand loading will also give the shooter the capability to produce a round that will function exceptionally well in whichever environment he desires. Some hand loaders will produce a round that works extremely well in a precision rifle competition (low recoil, flat trajectory, etc.), but may not perform to a standard needed for long-range hunting (insufficient kinetic energy).
I believe that precision rifle shooters must understand that a proper hand-loaded round may far exceed the accuracy and performance of almost any major/popular rifle cartridge on the market today, given the fact that the shooter understands the process of hand loading entirely.
Equipment needed:
- Presses
- Dies
- Scale
- Shell holders
- Priming tool
- Bullet puller
- Powder measure
- Case trimmer
- Primer pocket tools
The hand load/reload process
- Case cleaning (optional, recommended for fired cases)
- Case inspection (Look for cracks or other defects, and discard visibly imperfect cases. Bent case mouths may be repaired during resizing)
- Lubricate cases (Carbide dies do not require lubrication)
- Size/resize the case (For previously fired cases, primer is pressed out in this step with most die sets)
- Ream or swage crimp from primer pocket (reloading military cases only) or mill the primer pocket depth using a primer pocket uniformer tool
- Measure and trim the case length (as needed—rarely required with handgun cases)
- Deburr, ream case mouth, and size case neck (optional, as needed; trimmed cases need to be deburred). Some bench rest shooters also do outside neck turning at this stage to make the cartridge case have uniform thickness so that the bullet will be released with the most uniformity
- Clean primer pocket (optional—primer pockets will have deposits from combustion) and do flash hole uniforming (optional—generally, only bench rest shooters do this)
- Expand or chamfer case mouth (not required with boat tail rifle bullets)
- Clean the lubricant from the cases
- Seat a new primer (Primer pockets often become loose after multiple loadings. A lack of effort required to seat new primers indicates a loose primer pocket. Cases with loose primer pockets are usually discarded after crushing the case to prevent its reuse)
- Add a measured amount of powder (Critical step: Incorrect powder charges are extremely dangerous, both underweight as well as overweight)
- Seat the bullet in the case for the correct cartridge overall length (OAL) and for aligning bullet cannelure (if present) with case mouth
- Crimp the bullet in place (optional—some may hold the bullet with neck tension alone)
- Cartridge inspection
Most reloading manuals list their loads starting with the fastest powders and work down to the slower powders. The powders have been selected as only suitable, and are based in part on the loading density. If you are starting out by having to purchase powder, select one of the powders in the middle or slow end of the loading data list, suitable for the bullet you will be using.
At your work station, start by separating the brass by the brand or military manufacture/date stamp head.
Clean, resize, trim (nominally to .01″ less than the maximum allowable case length as specified in your load manual—the actual length is not as important as the lengths being uniform), and prime about 100 pieces of the same brand of brass with your favorite primer. Be sure that you use the same primers and bullets for all the cases.
Check your loading manual and determine the maximum charge suggested for your powder. Now determine how much adjustment on the powder measure will throw about one percent or slightly less of the weight of maximum charge of powder. (As an example, if the maximum load was 45.3 grains, you would determine the amount of adjustment of the measure that would give you about a 4/10 to 5/10 grain increment, often about 1/4 to 1/2 turn of the adjustment). Then, set your powder measure to throw a charge in the lower third of the charge weight range as recommended by your loading manual. Also note the maximum velocity indicated in your load manual so you have some idea of when you are approaching a maximum load.
Now seat the die so that bullets will be seated 10 to 20 thousandths off the lands or to the workable maximum overall length if they will be used in a magazine-fed firearm. Be sure to check your seating plug to ensure that it bears only on the ogive of the bullet and not the tip. Because bullet tips vary slightly in shape, seating a bullet by means of its tip leads to varying seating depths. It may be necessary to alter the seating plug by drilling it out slightly so it bears only on the ogive. Some manufacturers will custom cut seating plugs for you.
Setting a seating die for the ‘overall length’ should be done using one of the gauges that measure from the ogive and not the tip of the bullet. Sinclair and others make inexpensive gauges for this or you can fashion your own.
Head for the range with bag of primed cases, bullets, powder, powder measure, a single stage press, a seating die, and a ‘permanent’-type marking pen. All you will be doing is throwing powder charges and seating bullets, so how you mount the press and measure so it is useable at the range is up to you. Load your first five rounds, and using proper shooter fundamentals, fire them at an aiming point through the chronograph. Record group size, the velocity and the standard deviation for the string. Increase the charge one ‘increment’ by turning your adjusting screw on your powder measure as described above and shoot five more rounds at a separate aiming point. Continue this process until you start seeing signs of high pressure or reach maximum velocity.
If you squeeze out an excellent group, load one sample round with that load and label before adjusting the measure so you can weigh it later.
As velocities increase you should see obvious changes in group size. It should be readily apparent when you reach a velocity node the barrel likes. However, don’t stop at the first point where you get a tight group, as most rifles have two or more nodes. As you pass through each node, groups will open up again until you approach the next node. Stop only when you are at maximum velocity or pressure. Once there, you should have identified rough velocity nodes for the bullet’s weight.
Importance of the chronograph
In the days of yore (BC: before chronographs), it was necessary to blindly hunt for loads that worked. Once a good load was found, changing any component could render the whole process useless (since changing components varies pressure and velocity) and one pretty much had to start from scratch if anything changed. A chronograph provides direct insight into what your loads are doing, and what you need to do to make them work better. You will be able to immediately determine if a changed component produces velocity outside of the range the barrel likes. In most cases, simply adjusting the powder charge will correct the problem.
One of the best chronographs on the market is the CED Millennium 2 Chronograph. It is extremely accurate and stable, interfaces with RSI’s Shooting lab software, and can be fitted with infra-red sensors that will ‘see’ bullets under conditions (including total darkness) that would fail on other chronographs.
Measuring muzzle velocity is crucial for finding and identifying the most accurate load for your rifle, whether you reload or use factory ammo. Also, critical trajectory data can be gathered from this information.
The chronograph will also tell you if you are getting velocities higher than that of the reloading manuals, helping you to avoid dangerously high pressure building up in your rifle. The price for a good chronograph ranges from $90 to $300.00. The chronograph has two or three metal wire sensors on top of a sturdy metal casing that houses a computer, which measures the velocity of your bullet (or arrows, pellets, etc.) as it travels through the sensors in feet per second (fps) and will also record the number of shots, the high velocity, the low velocity, extreme spread (ES), the average velocity, and standard deviation (SD).
The high reading shows the fastest shot, the low reading shows the slowest shot, the average gives you the average of five shots or ten shots (called the shot string or ‘string’). The extreme spread (ES) is the fastest shot minus the slowest shot. The (ES) goal for the long-distance hunter should be within 30 fps or better. And 20 fps puts you at the beginning of competitive benchrest shooting. There is also standard deviation (SD) which is the measure of how close each shot’s velocity in the shot string will be to the ‘average.’ For the long-range marksman, 9 to 12 fps is good. The lower the (SD), the better.
Because factory ammo is already made, it is impossible to enhance the data of factory ammo. All the components of factory ammo come fixed. The best you can do with factory ammo is find the brand that shoots the smallest group, and when you do; buy up all of that particular lot and brand of that ammo. You will still be able to extend your shooting distance with factory ammo. The limit being, as far out as you can effectively practice and confirm your maximum shooting distance.
When testing with reloads or several different brands of factory ammo, the idea is to shoot the smallest shot group you can at 100 yards and use the data to determine which load or which brand of factory ammo is consistent. Keep this data, as you will need it later. Once the best hand-load or brand of factory ammo is found, shoot a couple of ‘strings’ out at 300 yards and see how your shots group there.
The goal should be 2.50 inches or better at 300 yards. This is sub-minute-of-angle. A One inch group at 300 yards puts you at the beginning of competitive benchrest shooting. A ½ inch group at 100 yards is very good; and a 1/4 inch group or all five shots inside of one hole is an excellent platform for a long-range rifle. If the chrono readings stay the same, and the shot groups remain small, you have a rifle that can be made to shoot at longer distances.
Fine-tuning your hand load
Now let’s say that your hand load is complete. How can we fine-tune our hand load to achieve its prime?
We should note that changing any component will affect the bullets performance. Bullets of the same weight but differing brand or shape will produce different velocities with the same powder charge. This anomaly is due to differences in jacket thickness, bullet bearing surface within the bore, gas seal on the base due to shape, hardness of core material, etc.
If you change bullet brands in your load, once you determine the new bullets velocity is above or below the previously identified nodes, all that should be required to make it shoot at a greater performance is to adjust the powder charge so the velocity is within the range your barrel likes.
(Featured image courtesy of mygunculture.com)
