We all know and appreciate when our car is tuned and running right versus when it's not. The same sort of principles apply to both a well tuned and accurized rifle, and cartridges precision tuned for that rifle, which will provide optimum performance. The process involved and time required to produce such cartridge loads are both easy to prepare with some attention to detail and usually doesn't require more than two to three afternoons at the range. Keeping complete records of the loads made and notes at the range will aid in analyzing results and documenting for future reference, those combinations that give excellent performance. If the steps outlined are not utilized, results will most likely be compromised and wrong conclusions could be made. Equally important to developing custom loads which influence final results, is having a rifle that also is "tuned" to its potential. This is commonly referred to as "accurizing and truing", it involves the action, chamber, headspace dimensions, crown finish, recoil lug, barrel, and glass-bedding/freefloating the barreled action into the stock. Trigger tuning also contributes to improved results on target. A further illustration that summarizes how important all these variables are for achieving optimum accuracy in a rifle, can be found in why one race car beats out all the others in a typical Winston Cup race or at Daytona 500. Having the fastest engine under the hood alone won't win the race. From how the car is prepared, chassis is set up for the track and conditions, to what tires to use and even their pressure, all contribute to making the difference. Then there's the driver with all his experience and knowledge, who can bring it all together along with the pit crew for a winning combination.
The three elements critical to achieving outstanding accuracy are the rifle, it's ammunition and the person behind the sights. This booklet offers suggestions and information that will help in bringing them all together. The following subjects in this section and the next when given attention will result in developing custom tuned precision loads for your rifle.
Industry standards for rifle manufacturers, while establishing the range for various tolerances do allow for slight differences. The differences not only vary from one company to the next, they also occur from one rifle to another. Ammunition manufacturers therefore produce cartridges set to tolerances that fall within theoretical industry averages for headspace dimensions, chamber fit and freebore clearance. Now, maybe you have one of the few rifles that factory loads shoot as well in as handloads, but for most rifles this usually means 1 1/2" to 2" plus size groups at 100 yards. At hunting ranges where 200 to over 500 yard shots may be common, group sizes with factory ammo may result in a poorly wounded game situation or one that gets away. Knowing exactly where that bullet is going to impact and being able to put it there, is what the following steps for producing precision handloads provides.

Cartridge case preparation involves a few simple yet key steps. First, cases should be of the same lot and manufacture. Measure case lengths after tubing, full-length sizing and set case trimmer length to shortest case length in lot to be loaded. Make sure cases are trimmed .005" less than maximum case length allowed for a particular cartridge (lengths are usually stated in reload books). Trim, debur and chamfer case mouth inside and out, then use Q-tip to remove cutting particles from within. Turn outside neck for consistent neck wall thickness, usually maintaining .015" to .016" depending on cartridge. This is measured with a dial caliper placed into case mouth opening at different points around circumference. Rechamfer lightly, case mouth (inside and out) after neck turning, and again, wipe with Q-tip. (Cases should be passed through full length sizer again to insure equal bullet tension will be set when they are seated.) Neck sizing only can be done after initial fire-forming of cases.

Primers: Next select correct primers for standard or magnum cases to be loaded and powder used. Double base extruded powders when used in the larger magnum cases are slower burning powders and require quality magnum primers such as Federal 215's for adequate flame and consistent ignition of powder charge. Your handload book will provide information as to which primers to use. Seating primers so they properly bottom in primer pocket in casehead is important. This insures correct firing pin contact and can be felt using a priming tool for seating. You can also run your finger over casehead after priming to "feel" that primer is slightly recessed below casehead. A primer pocket cutting tool can also be used for maintaining uniform depth, a step benchrest shooters do.

Powder selection is important for developing optimum loads that will give consistent performance for a given load being developed. As a general rule for rifle cartridge development, selecting medium burning to slow burning rate powders from your load book will usually provide best results for medium to medium-heavy bullets in a given cartridge. (A relative burning rate chart is provided at the end of this section.) An example of this for .30 caliber cartridges would be 150, 165 & 180 grain bullets are considered medium while 190, 200 & 220's heavy.

Consistent ignition and pressure levels contribute to more uniform velocities and tighter groups on target. Such results are usually obtained with cases that are filled or have slightly compressed powder loads Accurate measuring to within a granule or two (0.1 grain wte.) is important. (Refer to your handload book for powders and starting loads to use.)

Bullet seating depth and determining overall cartridge length are probably 80% key to developing optimum loads for any rifle. Variables to keep in mind when seating bullets are; cartridge fit and functioning in magazine well, bullets, distance to lands, and pressure levels influenced by seating depth of bullet. Equally important, one should keep detailed records of loads developed (bullet make, wte., powder, charge wte, & seating depth).
Determining optimum bullet seating depth will vary with type, shape, and weight of bullet used. Constructing a "dummy" round (case and bullet only) and putting black magic marker ink around bullet body to see if lands leave a mark on bullet and adjusting cartridge length until they don't is one way. Another is to slide a cleaning rod with tape over threaded opening or 1/4" wooden dowel (lumber or craft store) down the bore until it contacts closed bolt face (make sure it doesn't contact ejector) and score a hash mark on dowel flush to rifle's m rifle. Next, insert a bullet (only) into breech and with bolt removed, hold gently in place with a short length of dowel (12" long and masking tape to stock). Again slide long dowel down muzzle, marking dowel flush to muzzle when it gently contacts bullet tip. This determines maximum overall cartridge length (OAL) and you can make a dummy round to test functioning and bolt closure. The bullet should be seated .002" to .030" clearance from the lands to give proper overall cartridge length for hunting applications. Fine tuning the OAL length to find the "sweet spot" can only be accomplished through trial and error for each individual rifle/bullet make and weight combination. This approach does help set parameters to work within reducing some unnecessary development time and expense. Another note worth mentioning is, Barnes "X" bullets typically group best seated shorter (.050") from contacting lands. (Also measuring Barnes bullets and others (OAL) and selecting those within a +\- .002" total length deviation helps achieve tighter groups.) Completed cartridges still need to fit properly in the magazine with a minimum of .020" clearance between bullet tips and front wall. This factor will set maximum cartridge length rather than distance to lands in some rifles and chamberings. Remember too, the further out a bullet is seated the more volume is created and a few tenth's grain weight powder may have to be added to bring optimum velocity back up. Approach these steps in small increments and keep an eye out for any signs of excessive pressure. If bullets are seated to touch or almost touch the lands, pressure will increase and this usually requires reducing the powder load to safe pressure levels. A chronograph would be a great aid in measuring and determining both correct and consistent velocities. (Velocity is normally measured 15' from the mumle.)
Pressure signs such as flattened primer, ejector mark on case casehead or difficult extraction are serious warning signs and one should immediately determine the cause. A bullet seated too long or too short will increase pressure, as will too hot of a powder charge. Either switch to a slower burning powder and/or reduce load by 5%. Observing SAFE loading practices must be foremost at all times!

Powder Burning Rate Chart

The following list depicts only an approximate relative burning rate for powders shown. This list should not be used for any specific load development and we urge that any questions you may have regarding these powders be directed to the manufacturing source. Load data for any particular cartridge can be found In most common handloading books available. Always-start with light to medium loads shown as chamber dimensions vary from one rifle to the next.

PRECISION HANDLOADING STEPS

The following information is offered to illustrate precision handloading steps using the .300 Arnold cartridge for example, as the principles can be applied to any cartridge you handload.

COMPONENTS:

• 8mm Remington magnum brass
• Federal 215 magnum primers
• Barnes, Hornady, Nosier, Sierra, Speer and Swift bullets
• IMR 4350, IMR 4831, VIH/N-160, N-165, RL22 and IMR 7828 powders

TOOLS:

• .300 Arnold magnum die set (full length sizer and competition bullet seater)
• Loading press
• Case trimmer
• Neck turner
• Other reloading accessories
• Dial caliper

CASE PREPARATION:(Double check each step before proceeding to next step.)
Example Cartridge; .300 Arnold
New Brass:
Resizing:

1. Inspect flash hole, case and throat for uniformity.
2. If case mouth is bent, insert needle nose pliers into throat gently and rotate a full revolution or two to make mouth opening uniform.
3. Spray RCBS case lube on RCBS type lube pad. Let soak in five to ten minutes before rolling cases lightly on pad, 5 to 8 at a time. Then place upright on plastic case holder tray (loading block).
4. Set full-length sizing die and lock ring to bottom-out on cartridge case holder in press when a full stroke of handle is made.
5. Full length size a case once then rotate 90° and repeat step once more and do the same with other cases.
6. The next step is to trim GAL case to 2.840" (.300 Arnold). Then debur and chamfer case mouth inside/out (usually 5-6 quick, light revolutions with chamfer cutting tool). Wipe inside case mouth out with Q-tip.

Neck Turning

7. Set .30 caliber RCBS or FORSTER neck turning cutter using a .015" automotive feeler gauge. Turn one case (stopping .001" to .003" before junction with shoulder) and measure several points around inside mouth for recommended neck wall thickness with dial caliper. You may turn outside only or both inside and out. (By purchasing extra cutting tools, the inside throat reamers or pilot guides can be all ready to go for various caliber cartridges you load frequently.)
8. Re-chamfer case mouth 3 light revolutions inside and out. (Wipe brass cuttings out of throat with a Q-tip and outside of neck with paper towel.)
9. Re-full length size case after neck turning (step #7) to re-set neck diameter to properly "tension" bullet when seating step #12 is done. (Wipe lube off cases after step #9 or when cartridge is completed, an old kitchen or dish towel works best.)
10. Fully seat Fed'l 215 magnum primers (medium-firm pressure). Run finger over casehead to feel that primer is not protruding (below casehead) and fully seated.
11. Select powder and charge weight and measure each case charge the same.(After first zeroing your scale and then setting weights to charge wte. selected.) If you use a powder charger, N-160 and N-165 will throw easier than IMR powders. (Recommendation, measure each charge load out on a scale for precise consistency to the granule using a plastic cup to hold your powder and plastic teaspoon to tap onto scale pan.)

Bullet Seating:

12. After selecting bullets to use, you're now ready to seat them. (If you wish, measuring each bullet first as to length with a dial caliper and grouping in segregated rows. Selecting bullets that vary less than .0015" to .0020" in length will contribute to smaller groups on target.) The "competition" bullet seater in your die set by RCBS is excellent. After setting the main body and ring in press make sure bullet seater (top knurled knob) is set initially high. (1 click = .001" seating depth adjustment.) Seat your bullet for OAL of cartridge between 3.570" to 3.680" max (.300 Arnold). Once set to correct OAL, finish remainder of production run (or sets of 5 to 10 cartridges) checking OAL with dial calipers every third cartridge or so. (Don't worry if OAL varies slightly on exposed lead tip bullets as the amount of lead extended to tip point varies a hair.) Your bullet seater contacts bullet slightly below tip.
13. Record your loads (spiral notebook), powder/charge wte., bullet make, seating depth, etc. and how various combinations performed on paper at the range, so that your "better" loads are available to you for future reference. 
14. If you're loading cartridges for your rifle only, a preferred step benchrest shooters do and which extends cartridge case life and promotes accuracy is to just resize necks on once fired brass. The cases, after firing in your chamber, are "fire-formed" to that chamber and neck sizing only will, in most cases, tighten up your groups even more (typically, 1/4" to 1/2").To accomplish this (neck size only), loosen the ring on the full length sizer and raise the bottom opening of the die in your press, so at full stroke the die bottom stays above the shell holder by a l/16" gap. You still must trim to length and chamfer inside and out of case throat/neck opening before continuing with steps #10 through #13 above.
15. Neck turning again, may be necessary after cases have been fired and reloaded 3 or 4 times due to brass flow under pressure. (Stop outside turning just before neck/shoulder junction .001 - .003".)

Helpful Hints:

1. Hunting bullets should be seated short of touching the lands in bore .002" to .030" or so depending on bullet used. Each rifle is unique to itself and finding the precise "sweet spot" comes from trying different progressive seating depths and .5 grain powder charge increments in magnum rifles. (Try at least 5 to 10 rounds per specific load.)
2. Barnes "X" bullets should be seated (.040" to .050") lower in cartridge case than if they were to contact lands. (This is an approximate length difference to start with using Barnes "X' bullets. The "sweet spot" could be found at +\-.020" from that starting depth difference.)
3. On test loads for accuracy and optimum group size development, use a permanent marker on side of case abbreviating bullet make & wte., OAL cartridge length and powder/charge wte. used.
4. The bullet measuring hint mentioned in step #12 is very important when using Barnes "X" bullets and others. They and Hornady's vary in OAL more than other bullet brands we've measured. Best groups on target were always achieved using these bullets, when they were measured first to within a length of .0015" to .0020" of each other.
5. A suggestion you may wish to use when selecting a bullet in step #12 for developing your hunting loads; Nosier ballistic tips (green for .308 caliber) are what we use for most initial cartridge development work at Arnold Arms Co. They are of a boattail form & shape and approach match bullet performance for accuracy and consistency. Also, the 150 grain bullets are phenomenal blacktail, whitetail and antelope medicine; while the 180 grainer's are "number one" mule deer stoppers out to 1,000 yards. Nosier partition bullets may seat best .001" to .002" shorter OAL than ballistic tips for best groups. Hornady spire points are usually seated shorter (.030" to .040") OAL than partitions. Sierra's typically seat (.002" to .005") shorter than partitions, while Speer's group best seated shorter than Hornady's by (.035"). These seating variances are approximate, and are due to bullet shape and degree of curvature from point where bullet diameter first achieves "one caliber" and slope "Ogive"towards tip. (Actually, one should reference this position point by setting dial caliper .001" less than one caliber, .307" for .308 caliber, as this point contacts the lands first.)
6. Seating bullets to their best overall length (OAL) of the cartridge is not an exact science and varies slightly from one rifle to the next. Therefore, finding where that "sweet spot" is with a given bullet/powder combination for any cartridge involves a certain amount of trial and error better summarized as "experimentation within narrow limits". At least that's what all the foregoing information has intended to offer you in helping to achieve optimum cartridge loads for your rifle. (Optimum cartridge loads for hunting rifles equates to consistent groups of a 1/2" or less in size.) While Arnold Arms guarantees 1" or better group capabilit.v on all rifles the company manufactures, we have yet to have one shoot only 1" groups. Most shoot one caliber holes to .5" groups!

More hints:

7. Determining OAL cartridge: Cartridge overall length isn't just important in attaining optimum accuracy from your rifle, it's critical. That proverbial "sweet spot" where the cartridge length, bullet, powder charge and rifle used all come together, is usually found in most hunting rifles somewhere between .020" to .030" bullet ogive setback from the lands. As mentioned in the 'Precision Handloading' section, one can readily determine the maximum cartridge length using a 1/4" dowel or cleaning rod, selected bullet and a dial caliper.
   Next measuring the bullet's overall length should then be notated. Subtracting from this measurement the case neck length plus the additional initial setback from ogive/lands contact point (subtract another .020" to .030"). The remaining bullet length can be added to the length of a sized and trimmed case. This will give you the "potential" initial cartridge OAL for starters. If you use a boattail bullet subtract both the heel height(bullet base up to where boattail angles to one caliber point on rear portion of bullet) along with case neck length plus initial setback from lands (.020" to .030"). Remember this beginning cartridge length must also fit in the magazine without the bullet's tip contacting the magazine's forward wall. (Clearance should be a minimum of .020" for field use.)

To illustrate this process, let's take two bullets in .308 caliber using .300 Arnold.

Example 1)	Measurements to notate (use dial caliper): 180gr. Hornady bttl spire pt. 1.275" bullet length .150" length of heel .280" length of case neck .030" starting setback from lands 2.840" trimmed case length 3.760" max cartridge length measured with dowel down bore (magazine length maximum is 3.68" in a Remington rifle.)
Therefore:	.150" length of heel (boattail) + .280" length of case neck = .430" portion of bullet inside case + .030" starting setback length = .460" 1.275" - .460" = .815" + 2.840" = 3.655" starting OAL of cartridge.
Questions to ask:	a.) Is starting length less than max cartridge length? (Measured with a dowel down bore.) Answer: Yes. (3.655" vs. 3.760") b.) Will cartridge fit in magazine? Answer: Yes. (Magazine length 3.70" requires max. OAL 3.68". Therefore, ideal OAL cartridge length should be found somewhere between 3.645" OAL of cartridge and 3.675" for 1 80gr. Hornady. (In individual rifles, optimum length may be found to be slightly longer or somewhat shorter than starting length shown.)
Example 2)	180gr Nosier ballistic tip bttl.    Example: .300 Arnold 1.340" OAL of bullet .200" length of heel (boattail base) .280" length of case neck (.300 Arnold) 2.840" OAL of case (sized & trimmed) .030" initial bullet setback from lands
Therefore:	.200" length of bullet heel + .280" neck length + .030" initial setback to clear lands = .510" 1.340" - .510" = .830" remaining bullet length outside case mouth + 2.840" case length = 3.670" initial OAL length of cartridge
*Optimum OAL of cartridge should be found between 3.660" and 3.680" **Sometimes optimum length will be found with bullet seated deeper than this staring OAL of cartridge. (This will be found through trial & error to result in an OAL of 3.660" up to 3.68" maximum magazine length.)