|October 12, 2008, 10:06 PM||#1|
Join Date: September 9, 2008
Handloading for Accuracy
I wrote this article a few years ago. It was published in the .50 caliber shooters newsletter, but in no other format that I'm aware of.
I thought I might share it with everyone here. As this article is a few years old, some of the tools, equipment and techniques discussed may have been improved upon since, or may be obsolete.
Take it for what it is, take it for what you can use... enjoy.
Hand-loading for Accuracy
This article will discuss the components and procedures necessary, as well as their relationships to one another and to the rifle used, to produce an accurate center-fire rifle cartridge.
With the exception of the belted magnum group of cartridges, which require different resizing methods and some of the more complicated wildcat chamberings, this information in this article applies to any center-fire bottleneck rifle cartridge.
The information and procedures contained herein are intended for the hand-loader of, at least intermediate experience. Beginning re-loaders should initially content themselves with learning the basic concepts of producing safe, reliable ammunition.
There may be some items of interest to the advanced hand-loader, and at the very least, may provide alternate methods and theories to consider. My approach to learning is to listen to everything, consider it all, and ultimately, try the things that make sense.
As an aid to explaining some of the steps presented, a “reference” rifle and cartridge will be used.
A benchrest rifle, consisting of a Stolle “Panda” action, H&S Precision graphite stock, Jewell competition trigger and H&S “10X” match barrel chambered in a “tight neck” 6 PPC. This particular rifle has produced 5 shot groups as small as .042".
The 6 PPC, as used by the vast majority of benchrest competitors, is the most consistently accurate cartridge developed to date, due in part, to its balance of case dimensions, powder capacity and bullet used.
This rifle and chambering was selected as a reference because it will require the most steps to produce a finished cartridge.
Not all rifles are capable of producing sub MOA groups at 100 yards. It is up to the reader to determine if all or any of the information provided is of value in their particular application.
The bullet selected provides, arguably, the greatest single contribution to accuracy.
Begin by selecting a bullet that is the correct weight and/or length for the rifle barrel’s rate of twist. “Twist ratio” is the distance in inches the rifling rotates one complete turn around the inside diameter of a barrel. The barrel’s twist is what imparts the stabilizing “spin” on the bullet, too much or too little for a given bullet and stability and consequently accuracy, will suffer.
A needlessly high rate of twist will reduce accuracy because it will accentuate any imbalance in the bullet. An insufficient rate of twist and the bullet will not stabilize adequately to remain, in simple terms, “point on”.
Numerous articles have been written about the effects different rates of twist have on bullets in relationship to their diameter, length, potential velocity and weight. Virtually all barrel and bullet manufactures offer readily available twist data based on bullet weight, intended velocity and caliber. The best advice I can provide is to try the slowest twist recommended for a specific bullet weight or, inversely, the heaviest bullet suggested for a given twist that will be sufficiently stabilized.
A word of caution is in order when using heavy bullets. Deep seating long heavy bullets to accommodate a box magazine’s interior length will alter the internal capacity of the cartridge case. Refer to an appropriate reloading manual in determining safe powder types and charge weights.
The 6 PPC reference rifle is equipped with a 1:14" twist barrel. This twist was selected because, of the possible choices for use with a 68 grain bullet, arguably, the most popular bullet weight for the
6 PPC, it should offer the best combination of stability and accuracy.
As air density also has an effect on stability, in that dense air can upset a marginally stabilized bullet, a slightly faster 1:13" twist could have been chosen if the rifle were to be continuously used in cold climates and/or lower elevations. The simpler solution of course, unless blessed with a selection of otherwise identical barrels of differing twist rates, is to adjust up or down slightly on the bullet weight to accommodate climatic or geographic changes.
The next thing to consider is the type of bullet used. Will a match bullet be more accurate than a hunting bullet of the same weight and caliber? Statistically speaking, yes. Why? Because match bullets are made to a higher standard in regard to jacket concentricity, finished weight, finished dimension and rotational balance. Certainly, there are instances of a particular rifle and hunting bullet combination with the ability to produce the occasional one hole group, but to consistently put 5 shoots into the same ragged hole, group after group requires the consistency of a match bullet. In .22 and .30 caliber alone, there are well over 100 possible choices of match grade bullets from bullet makers both large and small, in weights for every available twist.
A primer is a primer, right? Wrong! Like any component available to the reloader, there are standard quality and match grade primers. To go into the details of primer manufacturing would require a separate article, but suffice to say, some are made more accurately than others. Not that the differences are great, it’s just that match primers are, much like match bullets, made with closer tolerances. In selecting a primer for the 6 PPC, I look to what is the most popular among winning benchrest and high-power competitors. Match primers from Federal, CCI and VihtaVouri are among the most common used in those disciplines, and for good reason, they are consistent.
The choice of which gunpowder to use can be simplified greatly. Choose a powder that gives adequate velocity, but more importantly, fills the case. A partially filed case allows the powder to shift and be distributed in a random fashion as the cartridge is handled or disturbed by recoil. This means that when the primer ignites, how the powder burns and how pressures develop will vary. Consistency, in regard to powder selection, will be improved from shot to shot as the case is filled closer to 100% capacity.
When deciding on a powder, I suggest referring to all reloading data available and cross-referencing that data for the cartridge selected. Some reloading manuals provide valuable information on load density, others for bullet seating depth, still others indicate best powder choice for accuracy within specific parameters such as bullet weight or barrel twist.
VihtaVouri N-133 is the preferred powder for the 6 PPC. Once again, in an attempt to not reinvent the wheel, this powder is used because it is one of the most popular among successful benchrest competitors using the 6 PPC cartridge. A small grain, extruded type powder, it meters very precisely through a measure and, within safe pressure guidelines, fills the case to 95% plus capacity while delivering superior uniformity.
Unlike the majority of re-loaders, benchrest competitors will reload their ammunition at the range, during the course of the match. This is done for two reasons; one is to control variables as they occur. Adjustments to powder charge weight, bullet seating depth, neck tension and bullet weight can be made to accommodate changes in wind, temperature, barometric pressure, humidity and elevation. Reason number two is that benchresters use only a small number of cases, usually 15 to 25 for an entire event, and must continually reload them.
Why not preload enough cases for the entire match? Because to improve the odds that every bullet fired will go into the same hole, they will take a quantity of raw, unfired cases, select the most identical ones from the lot, then weigh, measure, machine and fine-tuned them until they are for all intents and purposes, identical. From that number, any case, which does not send its bullet into the group, will be immediately discarded.
The second discrepancy from conventional reloading, is that in benchrest competition, powder is dispensed directly into the primed case from a precision measure; no scales are used at the range. Scales are only used initially to make a “powder chart” or “graph” indicating what amount of powder will be dispensed when the measure’s micrometer dial is set to a selected number. The shooter, during previous practice sessions, has established a range of usable powder charges, within safe pressure limits, and will adjust the measure to accommodate variables as previously stated.
Using a repeatable, consistent technique to throw the individual charges, variations in powder weights delivered to the case are typically no more than one tenth of a grain.
The cartridge case is the one component that, no matter how good it is, can be made better. The modifications detailed in the upcoming pages are those required to produce a case of competition quality. Lesser quality cases may be used, acceptable tolerances broadened, or some of the uniforming steps not taken but the finished results would be unacceptable to the individual trying to achieve the best possible accuracy.
Begin with a quantity of new or once fired cases. Purchase the best quality cases you can afford. Price is sometimes a good indicator, from brand to brand, of the inherent quality of the case.
The most important thing to look for is consistent case wall thickness.
Consider what competition shooters use, as those that are successful seldom skimp on the quality of brass. The better the quality of raw case, the better the finished product will be.
In the 6 PPC chambering, the most popular are the Lapua .220 Russian cases. Although expensive, these are considered to be the finest quality available for this application. As a parent cartridge, they must be sized up to 6MM, (.243 caliber) then fire-formed to the final 6 PPC dimensions. The Sako 6 PPC case is popular as well, and does not require any forming steps.
There are several manufacturers who produce match cases. For example, Federal Cartridge makes the high quality, Gold Medal Match case in all the popular civilian versions of NATO military chamberings such as .223 REM and .308 WIN.
Norma Precision produces cases that are, although not listed as match grade in their advertising, of exceptional consistency.
Different case brands, and even lot-to-lot variances of a single brand can vary in overall wall thickness. This particular point will be referred to again, later in the article.
Please read and reread this section before attempting any case uniforming procedures that are unfamiliar. Any attempts to achieve perfection require tools, preparation and patience. The minimum tool requirements are listed below.
A primer pocket “uniformer”. Not a scraper!
An inside flash hole de-burring tool.
A flash hole reamer.
A case length trimmer.
A case mouth inside/outside de-burring tool. Also referred to as a chamfering tool.
An outside neck turning tool with a neck turning/expander mandrel appropriate for the caliber used.
An expander body. This tool holds the turning mandrel in the loading press, necessary for a separate sizing procedure.
A metal dial caliper.
A powder measuring scale, preferably electronic, graduated in 0.1 grain increments.
A tubing micrometer, graduated in .0001" increments. (An acceptable alternative would be a case wall thickness gauge such as the RCBS “Casemaster” or NECO case gauge)
All these items are available from Sinclair International (www.sinclairint.com) or a similar precision shooting supplier. Most re-loaders will already have some of these tools.
Once the case selection is made, they must be measured and weighed. Using the tubing micrometer or case wall thickness gauge, measure the thickness of the brass, at the neck, in four places or every 90°. Cases with a variance of greater than .001" should be discarded if they are to be used in competition. An inconsistency of not more than .002" is satisfactory for non-competition use.
Now weigh the remaining cases. The acceptable difference in weight is an arguable point but as a general rule of thumb it should not exceed 0.5% of an individual cases weight. Once the cases are sorted by thickness and weight, proceed to the next step. (Save the culls, they can be used for test and tool set-up instead of the matched cases)
When a case is manufactured, the primer pocket and flash hole are “punched” through. This process can result in a number of inconsistencies which all require correction. The previously mentioned Norma Precision drills the flash holes in most of their cases in an effort to eliminate some of these imperfections.
Begin by cutting all the primer pockets to a uniform depth. This is done for two reasons, to ensure that the relationship of the primer to the firing pin is constant, and to provide a flat surface for the anvil legs of the primer to seat against. Should a case show no indication of being cut in the pocket base, discard it to the cull pile. When preparing a large quantity of cases, an adapter is available to put the uniformer into a cordless screwdriver.
The next step is to check the I.D. of all flash holes. Most cases have a .080" flash hole. Any found undersize should be drilled or reamed to ± .001" of the standard diameter. The Lapua .220 Russian case has a small .060" flash hole and actually must be reamed to .0625" to accept the passage of a standard de-capping pin, or a special .059" de-capping pin must be used.
Where the flash hole comes through on the inside of the case is the next area of concern. When a flash hole is punched, a ragged burr may be left inside, around it’s circumference. These burrs vary from case to case and cause a non-uniform distribution of the flame generated when the primer ignites, in turn causing inconsistent powder combustion.
There are two types of inside flash hole de-burring tools. Some have a stop shoulder at the cutting end and will cut to the correct depth, regardless of overall case length. Others, such as the RCBS tool use an adjustable collar that indexes on the case mouth. If using the latter, then all cases must be trimmed to an equal length and de-burred prior to de-burring the flash holes. Remove only enough material to make the area around the flash hole smooth and even, with a slight chamfer. Refrain from turning a straight flash hole into a large funnel, it is not advantageous to do this and may weaken the case.
The most common case length trimmers are the bench-mounted types such as the RCBS and Forster units, which hold the case by its head in an adjustable collet. A floating shaft with a piloted cutting head is inserted into the case mouth and rotated until the shaft’s adjustable stop bottoms against the tool body.
Use a cull case for set-up. Trim to the SAAMI recommended case length or, with the aid of a “chamber neck length gauge”, an accurate measurement can be made of the barrel’s chamber neck length and the cases trimmed accordingly to fit that chamber. Don’t forget to de-burr the inside and outside of the case necks.
Before continuing, a little bit about chambers. There are essentially four types of rifle chambers, not counting wildcats. The first, a standard SAAMI chamber, will be somewhere between the minimum and maximum dimension specifications for a given cartridge. The second type, a “loose” chamber, or a chamber at maximum specifications, may sometimes be referred to as a “military” chamber; these chambers in a military rifle are designated differently. For example, a .223 REM has the NATO metric designation of 5.56X45 in a military rifle. This extra clearance allows the cartridge to fit and fire in the chamber even if both are dirty or the cartridge case is slightly damaged. A case fired in a military chamber will rarely fit a standard or smaller chamber without full length resizing due to the excessive stretching that occurs to the case in both length and diameter. The third, a “match” chamber is reamed to the minimum specification of the SAAMI guidelines and may also have a shorter than normal throat or “lead” to accommodate a specific bullet type.
The fourth type is the custom chamber, typically minimum SAAMI specs for the case body, a “tight neck”, under SAAMI specification and, like a match chamber, a specific throat dimension.
Parts two and three coming up...
Shoulder Drive Nicholson Club
|October 12, 2008, 10:07 PM||#2|
Join Date: September 9, 2008
Handloading for Accuracy, part two
Based on the individual rifle, necks should be turned a little, a lot, or not at all.
The inside diameter of the chamber neck, the outside diameter of a loaded round and the total variance in wall thickness will be the determining factors. In any type of chamber, the reasons for turning the necks are so that the tension on the bullet can be made identical from case to case and that the bullet is presented concentric to the barrel throat.
If the case necks vary by .0005" or less, they have exceptional uniformity and typically would not require turning, for a standard chamber.
In a match type chamber it would be advisable to turn the necks only enough to obtain a .0001" case wall variation, assuming adequate room for neck expansion.
In a tight neck chamber, the necks must be turned not only to fit the chamber, but also to provide a small amount of clearance for the neck to expand and release the bullet upon firing.
My “tight neck” 6 PPC has a chamber neck diameter of .2620". A loaded round must be less than this dimension. The unturned wall thickness, times two, plus the bullet diameter add up to a loaded round neck diameter of .267". It will be necessary to turn from the neck wall a total of .003". This will be done in three steps. The first removing .0015", the second .001" and the last, a finishing cut of .0005". This will produce a loaded round diameter of .2610", allowing a minimum .001" total case neck expansion before contacting the chamber. Only a small amount of neck resizing, if any, will be required to reload these cases once turned.
A minimum specification chamber is desirable not only for accuracy, but for brass life as well. Sized brass, upon being fired will expand to the chamber dimensions then contract slightly.
A case, repeatedly full length resized, and used in a maximum specification chamber, may separate at the case head area or split along the body from the continuous expansion and compression process.
If the chamber is on the low side of the specification, when the case is resized, the amount of force applied to the case and the amount the brass must compress to return to it’s original unfired form is reduced. “Working” the brass as little as possible is what contributes to long case life.
Even in a SAAMI standard production rifle the clearance between the neck of a loaded round and the chamber neck can be substantial, although usually no more than .004" - .006"; occasionally it’s as much as .010". Quite a bit of room for the neck to expand, and this expansion coupled with repeated resizing of the neck will cause case necks to split.
If a deep hole gauge or I.D. micrometer is not available to measure the neck, try this; obtain a number of fired cases that have not been resized and measure the outside diameters of the necks. This will give an indication of the neck diameter in the rifles chamber. The case necks will measure .0005" to .002" smaller than the actual dimension in the barrel due to the brass’ ability to “spring back”, but it gives an indication of how much the case neck is expanding.
Should the difference in an unturned loaded round and the estimated chamber neck dimension be greater that .006" I recommend not turning the necks. Instead, try to find a brand of case with a thicker neck wall, which can be turned and still maintain a reasonable maximum clearance, or a case brand with no more than .0005" wall thickness difference.
Neck turning made easy.
Obtain a full length sizing die. Remove the I.D. sizing button and decapping pin from the die. Using a cull case, adjust the die according to manufacture’s instructions. Lubricate then size all the cases. This will compress the neck, move the high spots to the inside diameter and insure initial dimensional uniformity.
This next step is where the “expander body” previously mentioned comes into play. Insert the appropriate neck mandrel into the expander body and install it in the press.
Lubricate inside the neck of the cull case and adjust the expander body so that the full diameter of the mandrel just goes all the way past the base of the case neck when the press is at the top of it’s stroke.
Lube inside the case necks as well as the mandrel shaft, and then insert the mandrel into each case. Stroke the press a few times to expand the inside of the neck, until only slight resistance is felt.
Why do this? Well, the first step is to push the imperfections to the inside of the neck. The second step is to force the imperfections to the outside where they can be removed with the neck turning tool. This also insures that the case neck I.D. is perfectly round and a snug fit on the turning mandrel.
The most common neck turning tool consists of steel or aluminum body with a hole bored through to accept a mandrel; perpendicular to the mandrel is an adjustable cutting bit. In kit form, the tool will also come with a clamp to securely hold the case.
Begin by inserting the mandrel into the tool body. Second, retract the cutting bit so that it’s at least .250" away from the mandrel shaft. Using the same cull case since the beginning of this process, insert the case into the case clamp tool and “screw” it onto the mandrel shaft until it bottoms against the mandrel shoulder.
Adjust the position of the mandrel so that the cutting bit’s outside edge comes within .005" - .010" of where the case neck and shoulder angles intersect. This is done to avoid the possibility of cutting into the shoulder. If the bullets used will seat deeper than this junction then it will be necessary to cut slightly into the shoulder to prevent a ridge from forming in the neck I.D.
Tighten the mandrel locking screw. Measure the mandrel’s position in the tool body with a dial caliper and write it down along with the case brand for future reference.
Remove the case. Using a blade type feeler gauge and assuming that at least .001" of brass must be removed, start with a blade .001" less than the maximum wall thickness of the cases measured, place the feeler gauge between mandrel and cutter bit and adjust the bit toward the mandrel until you feel the slight drag of the blade between the two.
A “slight” drag should allow the feeler gauge to slide back and forth without being scarred or snagged by the cutting bit. If unsure, use a .001" thicker gauge. Brass is easy to remove from the case, but truly difficult to put back.
Lubricate the case necks, both inside and out. Lube the mandrel shaft as well. Insert the first case in the case holder and slide the case onto the mandrel, begin “screwing” the case down the mandrels shaft until it bottoms on the shoulder. Don’t feed the case into the cutter too quickly, about a 1/32nd to 1/16th of an inch per revolution. If the feed speed used is too quick it will leave “grooves” in the neck. Use a small paintbrush to remove excess brass chips from the mandrel, cutter bit and case. As with most of these tools, if there are a large number of cases to be turned, adaptors are available that will allow the use of a cordless screwdriver.
This first pass removes most of the “high spots” and this may be far enough. Should additional passes be required, don’t be in a hurry; remove no more that .001" of brass at a time. As the final desired dimension is approached, remove .0005" or less per pass. After neck turning all the cases, touch them up inside and out with the deburring tool. Clean the cases thoroughly.
Part 3 coming up...
Shoulder Drive Nicholson Club
|October 12, 2008, 10:08 PM||#3|
Join Date: September 9, 2008
Handloading for Accuracy, part 3
Assembling the cartridge.
What happens next depends on the equipment used. There are essentially two types of rifle dies, the full length sizing die which, dependant on adjustment depth, will size only the neck at the least, to the entire case body, including pushing the shoulder back, closer to the case head, when adjusted to it’s maximum. Read the manufacturers instructions for proper use of this type of die and use cull cases to set it up in the press.
The second type, a neck sizing only die, does just as the name implies, it resizes just the neck of the cartridge. The neck die is the most popular among benchrest shooters and varmint hunters using bolt action or single shot rifles.
The reason for this is, when the cases are used in only one rifle, having conformed to that rifles chamber, there is no need to constantly resize the entire case. The only time a full length sizing die may be needed would be to “bump” the case shoulder back a small amount, usually .0005" to .0015", should it become difficult to close the bolt or breach block. As an added benefit, neck sizing only dies require no lubrication.
A full length sizing die should be used exclusively only if the cases are to be used in more than one bolt action or single shot rifle, any dangerous game rifle where function is critical, or a semi-automatic or lever action rifle.
Actually, it is not absolutely mandatory to use full length sized cartridges in some match grade semi-autos. When loaded singly, and not from a full magazine, there is no reason to full length size the case unless they become to tight to allow the rifle to function properly.
Another category of die is the neck bushing die. They are identical to the dies previously mentioned except that, as the name implies, they use an interchangeable bushing, available in .001" increments, which allows the user complete control over the amount of neck tension applied to the bullet. The standard type dies may, dependant on their internal dimension and the wall thickness of the cases used, may apply too much or not enough neck tension to the bullet.
A brief word about I.D. sizing buttons. All sizing dies, with the exception of hand dies, come with an I.D. sizing button, in line with the decapping pin. The button is designed to, regardless of how much the die body compresses the neck, return the neck I.D to a dimension large enough to accept a bullet and small enough to apply adequate tension. Due to their small bearing surface, they are highly unreliable in regard to returning the case neck back to a consistent diameter.
Redding, who’s dies I am familiar with, make a type ”S” die, in both full length and neck only, which allows the user to remove the sizing button but retain the decapping pin. Other die brands may or may not have this feature.
The final and preferred die type is the hand held die; it’s used in conjunction with a small, arbor type press rather than a conventional reloading press. These are the dies, in particular the bushing type, neck sizing only die that most benchrest competitors use. They are small, light weight, (read, easy to pack and carry to the range) extremely precise and simple to use. They do not lend themselves well however, to volume reloading. Sinclair International carries the Wilson brand of hand dies, which are the most common.
Determining Bullet Seating Depth.
I use two tools, A Stony Point Chamber-All gauge and Sinclair Bullet Comparator. The Stony Point tool easily permits establishing the location of the bullet in the case when it just touches the rifling lands. The Sinclair comparator, contacting the bullets “ogive” (the location at which the bullet’s point starts and the bearing surface ends) as a constant point of reference, allows a repeatable measurement of bullet positioning for accurately measuring the OAL of the cartridge. Both tools are used with a dial caliper.
Most rifles will shoot best when the bullet ogive is somewhere between just touching the lands to .025" off the lands. Begin by adjusting the bullet seating die to seat the bullet .005" to .010" off the lands. If needed, alter this adjustment in increments of plus or minus .005" until best accuracy is obtained.
Never seat the bullets hard into the lands as it may cause difficulty extracting a loaded round.
The only limiting factor to this is when inserting loading your rounds into a box magazine; this can limit the cartridge’s overall length.
When searching for absolute accuracy, I recommend loading each round individually into the chamber, this permits long bullet seating if needed and eliminates the need for the additional neck tension required to keep a bullet from moving in it’s case under recoil, as it rests in the magazine. Also, a taper or roll crimp may be necessary in any rifle, when feed from a box or tube type magazine.
When using a bushing type die, as a starting point, select a bushing that is approximately .003" to .004" smaller than the O.D. neck measurement of a loaded cartridge. This will ensure adequate tension of the bullet. At some point, trying a larger I.D. bushing to reduce the tension on the bullet might improve accuracy.
Clean the cases if necessary, and prime them. I use a Lee Auto-Prime hand held priming tool, they are inexpensive and provide and adequate “feel” for seating the primers. Seat primers until they just touch bottom, then apply a very small amount of additional pressure to “preload” them. This will ensure reliable and consistent primer ignition.
Charging the case with powder is the next to last step. The appropriate powder, will fill the case to at the least, somewhere between the upper part of the shoulder, to at the most, the bottom third of the neck. (This is only a guideline; some “slow” powders, although correct for the cartridge and bullet used, may fill the case to the top of the case mouth and would be a “compressed charge”)
To practice dispensing powder charges without benefit of a scale, try this; cycle the measure a few times to settle the powder then throw a charge into a powder scale tray and weigh it.
Got it? Now remove that charge, and throw ten charges in a row into the tray and weigh that, divide the measurement by 10. Did it come out the same? Maybe 0.1 to 0.2 grain difference, more or less? If the variance was greater than that, try “tapping” the handle at the top and bottom of each stroke. Better? As I said earlier, 99.9% of benchrest shooters don’t use a scale other than to produce a powder graph for the powder of choice.
A word to those with progressive reloading presses. Every procedure described so far can be done on a progressive press. Although quality is not usually synonymous with quantity, a properly set-up progressive can be made to produce match grade ammunition.
As proof of this, several years ago, a Dillon Precision employee and practiced benchrest shooter competed in matches in Phoenix, AZ., using a Dillon 550 progressive press, he often finished in the top 10.
Seating the bullet.
As I have no control over the press used by the reader, trying to describe seating “feel” will be difficult at best. The more leverage available, the less feel as you seat the bullet. Most important is that every time a bullet is seated, it should feel the same. If one slides in with smooth even resistance, one falls in and the next requires extra effort then the necks do not have consistent wall thickness or concentricity. Variable neck tension will produce variable points of impact on target; it’s similar to having ammunition with each round having a different powder charge or seating depth.
Tailoring the Load.
Following these steps should produce loaded rounds that are as good, if not better than the best match ammunition sold. If the load does not produce the desired accuracy, try adjusting the bullet seating depth in .005" increments closer to or farther away from the lands, within that .025" range. Try using slightly less powder. If loading rounds one at a time and using a bushing type die, try reducing neck tension on the bullet by using a larger bushing.
Only if it is felt that the rifle and ammo are not yet meeting their potential, should you try different components.
All of “what else” in detail is another article for another time. A quick overview of some important things to consider is as follows:
1. Use stable rests that will repeatedly hold the rifle exactly on target from shot to shot.
2. Make sure you are using “enough” scope. High magnification allows more exact positioning of the reticule on the target.
3. The target should also be matched to the scope, if your reticule subtends (covers) your aiming point, it will be hard to hold repeatedly on the exact same spot. A good example of this would be trying to center a 1.50 MOA dot on a 1.0 MOA target spot. Instead, find or make a target with a 1.75 to 2.0 MOA I.D. circle to center the reticule dot inside.
4. Use some sort of wind direction and speed indicator; a 2 ft. long piece of nylon surveyor’s tape attached to a 3 to 4 ft. wooden stake, placed 10 to 15 yards from the firing line works well.
The effect of wind on a bullets flight is exponential. If a wind alters a bullet’s flight at or near the muzzle, then the angle of that deviation will increase for the time or distance that the bullet is in flight. A deviation occurring near the target will have less effect because the time or distance to impact is reduced.
5. Hold the rifle the same for every shot. Some rifles prefer a “soft hold”, some a “hard hold”.
6. A gun with a 3.5 lb. or heavier trigger, or a trigger with “creep” or one that “stacks” pressure will make it very difficult to hold the gun on target until the trigger “breaks”. You can check this by dry firing at the target and watching the reticule, does it move from point of aim as the trigger is pressed? Then the trigger is to heavy for accuracy work. Does it bounce away from point of aim when the firing pin falls? Then the rests used are not sufficiently firm and stable, see # 1.
7. Most rifles will send the first one or two bullets from a cool, clean barrel to a different point of impact, if this is so for your rifle, fire those “fouling” shots at a separate “fouler” target. Amazingly enough, it might end up being the best “group” of the day!
8. All rifle barrels, regardless of thickness, distort to some degree as they warm up. When using a thin-barreled rifle, allow a few minutes for the barrel to cool between each shot.
9. Ever wondered why 3 shots go into a tight little cluster and 2 go “some place else”?
Every aspect of the shot should be identical to the one before it.
May all your bullets go through the same hole.
Shoulder Drive Nicholson Club