Countless books, articles, video series and even classes have been devoted to the subject of long-range shooting and the factory- or hand-loaded ammunition that's needed to achieve success. Many shooters can't agree on what distance constitutes ''long range,'' much less the specific steps and equipment needed for that first-shot hit or holding a tight group. While 600 yds. is considered long range by many, others consider it midrange. By disregarding shooter ability or rifle accuracy, and focusing on ammunition specifically, we can easily consider 500 yds., 600 yds. and beyond as long range. This distance is where we really start to see variations in components or loading techniques that affect the bullet's point of impact or group size. Loads that are acceptable at 300 yds. might not have the consistency required for a 600-yd. shot. Of course, some shooters, such as benchrest competitors, will make the point that their 300-yd. loads require the same amount of prep and consistency as their long-range loads. However, small inconsistencies in ammo due to velocity variation or mixed cases don't affect most recreational or competitive shooters at close range. For example, assume you are shooting a .223 Rem. with a 75-gr. BTHP bullet loaded to 2,700 fps with a velocity extreme variation of 50 fps. That means in your five-shot string, you had shots that were as slow as 2,675 fps and shots that were as fast as 2,725 fps.
So, at 200 yds. (assuming your rifle is shooting perfectly), you will have a vertical string of 0.3'' - a variation that will go unnoticed by most shooters when shooting at 200 yds. But, when you stretch the range out to 600 yds., that same 50 fps velocity variation now becomes 4.8''. This variation, coupled with the accuracy limitations of the rifle, can result in a miss on small targets. At 1,000 yds., the vertical string nears 20''. Even if the rifle is capable of shooting 1/2 minute (5'' at 1,000 yds.) the combination of vertical stringing (19.9'') and rifle capability (5'') is over twice the size of the 10'' bulls-eye used in 1,000-yd. F-Class competitions. Obviously, velocity extreme variation (EV) is something we want to keep to a minimum.
The bullet itself is the foundation for accurate ammunition. Finding the best bullet for your particular firearm/barrel requires some trial and error. It's important to test these projectiles at longer ranges rather than relying on 100- to 200-yd. accuracy.
For long-range consistency, sort and remove based on weight and length variations. Keep in mind, larger bullets (.30 cal. and above) can withstand slightly more weight variation than smaller bullets, and bullet length is important for consistency. It is best to measure bullet length from the base to ogive location using a bullet comparator, while making sure to keep variation less than 0.005'';.
Bullets used for long-range shooting feature low drag profiles that include a long ogive and boattail base. The measurement of how ''slippery'' a bullet is in the air is known as the ballistic coefficient. The higher the ballistic coefficient, the less effect drag will have on the bullet. Keep in mind that the longer and more aggressive the profile of the bullet is, the harder it will be to stabilize and shoot accurately.
1. Secant Ogive Profile: The geometric profile works to produce low drag and flatter trajectories. The secant ogive design also provides the optimum bearing surface for stability in flight and the best ballistic coefficient possible.
2. Swaged Lead Core: The swaging process provides excellent uniformity and balance for consistent performance and accuracy.
3. AMP Jacket: The jacket has virtually zero tolerance for concentricity and near-zero wall-thickness variation.
4. Boattail: The angle and length of the boattail is unique to each caliber and weight of Match and A-MAX bullets to maximize ballistic coefficient and accuracy.
POWDERS AND PRIMERS
Propellants, much like bullets, require some testing to find the best results. Fine-grained powders tend to meter the easiest. Where shorter distances (300 yds. and less) are minimally affected by 0.3 gr. in variation, long-range shooting requires the variation to be as low as possible, which is why carefully weighing each charge is beneficial.
Consistency requires the least amount of temperature sensitivity. Single-base propellants (nitrocellulose) have significantly less performance variation with temperature fluctuation than double-base (nitrocellulose plus nitroglycerin) powders. This is important if you expect to shoot in different climates. Examples of single-base powders include IMR, Hodgdon and Vihtavuori 100 series.
• Keep in mind that accuracy is more important than speed at long range.
• Don’t give up consistency to gain an extra 40 fps.
• Propellants with faster burn rates for the cartridge you are loading tend to produce better accuracy.• Just like you did with projectiles and propellants, spend some time experimenting with different primers.
• Avoid using magnum primers unless you’re shooting a magnum. Magnum primers provide a more violent ignition, which increases inconsistency in non-magnum cases.
Getting a true muzzle velocity for a cartridge with a chronograph can be a challenge. Outdoor lighting conditions constantly change and the slightest variation in the angle of the sensors can give you an incorrect reading, and an incorrect muzzle velocity reading can make it difficult to hit a long-range target.
One of the best ways to get the actual muzzle velocity of your favored round is to do a trajectory validation in the field or at the shooting range. Many ballistic calculators have an option for determining your muzzle velocity. By first providing a ballistic coefficient (BC) and true sight-in range, then shooting at a further distance and measuring the drop from point-of-aim, an accurate muzzle velocity can be calculated. Trajectory validations can help you determine an accurate muzzle velocity or ballistic coefficient of your projectile. Perhaps the best function of a chronograph is comparing one load to another and measuring velocity extreme variation. Keep working on your loads to get your extreme variation down near 25 to 35 fps or better. Single-digit extreme variations are obtainable when everything (cartridge, chamber, barrel etc.) is perfect.
Cartridge cases are important as they bring all of the components together. Weight and capacity vary from one manufacturer to another. Sorting cases by manufacturer is essential; even keeping cases separated by manufacturing lot adds to consistency. Separating cases by the number of times they’ve been fired is also recommended. For long-range consistency, sort cases in 1-gr. weight increments. Deburr flash holes and ensure that primer-pocket depths are uniform. This helps provide a more even primer ignition and flash. Neck thickness is also very important for consistency. When the propellant ignites and the case expands to fill the chamber, a neck thickness issue would force one part of the neck to touch the chamber before the rest of the neck, promoting inconsistency. Using a neck thickness tool or ball micrometer can help you weed out any affected cases. Some shooters find success in building tight chambers and turning (removing brass from) the necks of their cartridge cases to fit.
When handloading, there are specific steps and equipment that can help maximize both consistency and accuracy. When a cartridge is fired, it expands to the walls of the chamber. When reloading that cartridge case, you have the option of full-length resizing the whole case back to its original size, or simply sizing the neck down and leaving the body the size of your chamber. Consistency can be gained with neck sizing. Much like case-neck consistency, if the case body expands and touches one side of the chamber first, rather than contacting all sides evenly, it can lead to inconsistency. Leaving the body the size of the chamber lessens the chance of this occurring. Of course, there are limitations to neck sizing. You only want to use neck-sized ammunition in the gun/chamber it was originally fired in. Also, it is not recommended in semiautomatics as it can lead to feeding issues. Neck sizing without pushing the case shoulder back can make it difficult to close the bolt. Using die sets that feature a floating-style bullets seating stem can help ensure that the bullet is seated straight in the cartridge case. When a bullet is not seated straight, you can visually see a wobble in the bullet when rolling the cartridge on a hard surface. This wobble, or runout, can affect the accuracy of the load. Runout should be kept below .0004'' for long-range shooting. It's also helpful to use seating stems that match the profile of the bullet you are using.
CARTRIDGE OVERALL LENGTH
When seating bullets, experiment with various jumps to the lands (where the rifling starts in your barrel) to establish the most accurate load. Using effective tools can help in this process immensely. Typically, a short jump of 0.000''-.003'' provides the best accuracy. Long-range bullets typically have long ogives which tend to shoot best seated on or into the rifling. Remember, measuring to the ogive is a more consistent measurement than measuring to the bullet tip.
Shooters who lack the time for handloading, or who don't wish to invest in the necessary equipment, have viable alternatives with factory-match ammunition in a number of popular calibers.
Improving on factory ammunition by handloading is not as easy as it once was. Factory-match loads can provide extremely good consistency. Some factory loads can also reach velocities using proprietary powder blends that handloaders cannot achieve with off-the-shelf propellants within established pressure limits.
- 367 views