Reloading Specification
Reloading Specification for factory built rifles
We have produced custom-built rounds for shooters across the UK and Ireland for the purpose of hunting large African game as well as indigenous British species producing excellent consistent results.
Improving accuracy by careful case preparation.
In our opinion case preparation can shrink your group from the standard factory ammo group of around 1" to ¼". We have tried to highlight the major operation and critical points to achieve maximum accuracy for hunting loads, briefly explaining why it is necessary to carry out each step.
Primer Pocket - we recommend the use of the K&M carbide primer pocket tool.
When you purchase new brass, this tool will cut the primer pocket to the correct depth, whilst remaining with SAAMI specs. This tool can be manually turned or used in conjunction with a cordless drill.
Flash Hole Burr - When brass is formed and they punch out the flash hole, a tiny raised burr is left around the edge of the flash hole, where it enters the inside of the case. The theory is that this burr could cause variable ignition from round to round dependant on the size of the burr and location.
The K&M's internal flash hole de-burring tool is simply a tiny centre drill in a mandrel that will cut away the burr with limited depth. A couple of turns on each new case are all that is needed to remove the burr and makes the flash hole uniform. This application only needs doing once in the case life.
Case Length Trimming - To obtain good consistent accuracy, you need to have all your cases the same length and the necks cut square. If one side of the case neck is longer than the other, it will tend to tip the base of the bullet to the side as it leaves the case. we use a Wilson Case Trimmer; this case trimmer is unique, compared to most, because of the way the case is held during the trimming operation. Correct alignment is assured, as the cartridge case is supported by the case body holder, which simulates a rifle chamber. Cases will be trimmed squarely regardless of off set heads or varying neck diameters.
Neck Mouth Chamfering - After you trim the case length, there will be a burr on the inside and outside of the case mouth. Use one of the many standard neck de-burring tools to remove the sharp corners from the case neck. This process is a very important step to make seating of the bullet easier and smoother without damaging the bullet when loading.
Outside Case Neck Turning - Most cases have varying wall thickness; this can cause misalignment of the bullet when the round is chambered. At this point you will really start to get true accuracy. Use the Sinclair NT-3000 Neck Turning Tool. Neck turning provides a neck with uniform wall thickness, helping to centre the bullet on the bore axis. Neck turning aims to cut excess brass from cases, which have large variations in the wall thickness.
Neck Sizing - We have achieved better accuracy and case life by only neck sizing the brass, instead of full length sizing each time you reload. Most deluxe die set comes with three dies per set, full-length die, neck die and a seating die. When you fire a round in your rifle, the brass case expands to fit your chamber. From then on if you only neck size, about ¾ or so of the neck, the case will fit your chamber much tighter. Usually ¾ of the neck gripping the bullet is sufficient to hold the bullet in place. If you do not have a neck die, you can compromise with your full-length die by lifting the die up slightly in the press. With most tapered cases this process will achieve the same result.
Primers – We have found that changing or mixing primers can greatly alter the group and performance. Why re-invent the wheel. All reloading manuals have data showing powder charges and the components used that helped produce that group. Read the small print before you purchase your components.
Propellants & Powders - There are many producers of powder and with a range of comprehensive manuals to guide you to choosing the correct load. It is very important to load with the correct powder, which will burn the within the length of the barrel and not outside the barrel giving you a large flash of burning powder. This is just wasted energy and produces erratic groups. Maximum powder charges do not always produce the most accurate groups. Never exceed the manufacturers recommendation on maximum powder charge. We recommend that you use a burning rate chart which give you the comparable burning rates of each manufactures powders and try different powder of equal burning rates suitable to each calibre and load development.
Bullet Seating Depth - Each rifle performs best at a particular seating depth called the overall cartridge length (OAL). Small changes in the clearance between the bullet and the rifling can make a big difference in accuracy. Most often seating bullets close to the rifling will improve accuracy. There are many tools on the market for measuring the overall cartridge length (OAL). We use the Stoney Point OAL gauge to determine a starting point for the bullet seating depth. This allows you to precisely regulate the bullet’s clearance from the lands (called free- travel). Never seat bullets closer than 0.010" from the lands. If you do so, there is high risk with hunting rifles when you come to unload a chambered round, the bullet head could become detached from the case and stuck in the barrel, spreading powder throughout the action and trigger assembly, which is not good when you are in the middle of nowhere.
Measuring cartridge lengths across the bullet's tips isn't a reliable method of the OAL. It is not uncommon to have a variation of up to 0.025" to exist from round to round. Bullets points can vary considerably due to the way in which bullets are made.
The Stoney Point Bullet Comparator provides a reliable measuring surface to the ogive of the bullet, resulting in consistent OAL every time.
Starting 0.010" back from the lands, load batches 3 - 5 rounds for testing. Working back, seating in increments of 0.010" until your group becomes proportionate to what you want to achieve, this may result in a OAL of 0.060" - 0.080" from the lands.
To shoot tight groups you must have the rifle barrel in tip top order and the trigger breaking clean. If you are stuck or have any problems contact me and I will assist you the best I can.