Dan Newberry’s – Optimal Charge Weight Load Development – Instructions

Warning! You are assumed to be an experienced handloader who follows safe handloading practices. If you have yet to read and understand the basic instructions in a reputable loading manual (such as Sierra, Lyman, Speer, Nosler, Lee, or Hornady), please DO NOT continue here until you have done so. I do not intend to bring the novice up to speed on case prep, safe bullet seating length, etc. Scores of volumes are written on these fundamental handloading issues, so repeating such instructions here would seem redundant. (as directed by Dan Newberry himself)

1. Decide on the bullet you want to use.
2. Choose a powder. This is the most crucial step in the complete process. As a rule, you should choose the slowest burning powder practical. There seem to be plenty of exceptions here, so if you have it on good authority that a slightly faster powder works well with the bullet/cartridge combo you are using, feel free to choose it. A couple of examples would be IMR 4350 in the 30-06 and IMR 3031 in the
3. .243 Winchester. When in doubt, consult the Nosler manual for their “most accurate powder evaluated.” That powder always gives satisfactory results in the application listed.
4. Consult at least three load data sources for the maximum charge weight for the powder you have selected. Powder manufacturers are the most reliable sources. Then, decide on your maximum charge.
5. Back away from the maximum charge by 7 to 10 per cent and load one test round with this charge. Add 2% to the charge weight and load another cartridge with that charge. Load a third test cartridge with the following 2% graduation. You will use these three cartridges for sighters and, more importantly, to determine the pressure tolerance in your rifle.
6. Add another 2% to the charge level used in cartridge #3 of step 4, and load three rounds with this charge weight. Add .7% to 1% to this charge, and load three more. Add that same graduation again and load three more. Continue adding the chosen graduation until you have moved ONE increment above your chosen maximum powder charge.
7. The seating depth for all test loads should, of course, be the same. I usually seat the bullet a calibre’s depth into the case or to magazine length–whichever is shorter. I do not believe loading to approach the lands is necessary or desirable in most situations. So long as the bullets are seated straight, with as little runout as possible, the advantages of loading close to the lands are over-stated. This said, ensure your seating depth does not cram the bullet into the lands. Stay at least .020″ or so off the land for these exercises.
8. The primer brand you choose is entirely up to you. Use magnum primers only with magnum chamberings, as their added pressure can distort the OCW conclusions on standard chamberings.
9. At the range, you should set up 5 to 7 targets at 100 yards. The number of targets you use will depend on how many “sets” of cartridges you loaded. Be sure the targets are identical and level. I like to use a simple black square drawn on a white background with a significant felt tip marker. I drew a square about 3/4″ (interior dimension) for my 9-power scope setting, which allows a “tight fit” of the crosshairs in the square and, thus, a repeatable sight picture. For higher power scopes, draw the square more diminutively, and vice versa.
10. You can also put up one “sighter” target and use the initial reduced rounds to get the POI on paper, as close to the bullseye as possible.
11. Your barrel should, of course, be clean before starting. Depending on the number of rounds you will fire, you may decide that it is necessary to clean halfway through the string, fire a couple of fowlers, and allow a couple of minutes to cool before continuing. With custom barrels, you may be able to fire 25 shots or more before fouling begins spoiling group sizes. Before cleaning, I only fire up to 15 to 18 shots with factory barrels. This is all relative, of course.
12. After you have fired the sighters and confirmed that there are no pressure signs (hard bolt lift, flattened primers, etc.), you allow the barrel to cool for an adequate amount of time (use common sense–the hotter it is outside, the longer it will need to cool) you will then fire your first shot from the first group of the graduated charges. You fire this shot at the target number.
13. Allow the barrel to cool, then fire a shot from the second graduation at target number 2. Wait for the barrel to cool, then fire a shot from the third graduation at target number 3. Continue this “round robin” sequence until you have tried all the targets three times. At this point, you will have a three-shot group for each target.
14. It is assumed that you are an experienced reloader and know to watch for pressure signs on each increasing charge. Fire the subsequent charge only if there are no pressure signs on the previous charge. You can safely fire the heaviest charge you loaded so long as the following charge under it shows no pressure signs. This “heaviest charge” should be about 1% over your selected maximum charge but will be safe if the following lowest graduation shows no pressure signs.
15. Triangulate the groups. This means connecting all three shots in a triangular form, determining the group’s centre, and plotting that point on the target. Measure this point’s distance and direction from the bullseye and record the information somewhere on the target. Do this for all the targets. If you have a called flyer, you should discount that shot or replace it in the group if you have an additional round loaded with that charge.
16. You will now look for the three groups closest to hitting the same POI (point of impact) on the targets. The trend of the groups should be evident, usually (but not always!) going from low and favouring one side to high and favouring the other. However, along the progression, a string of at least three groups should hit the target at the same relative point.
17. After carefully measuring group sizes, distances, and directions from the bullseye, you will know which three groups come the closest to hitting the target in the same POI. You now choose the powder charge, representing this string’s centre. For example, if 34.7, 35.0, and 35.3 grains are all grouped about 1.5 inches high and about 3/4 of an inch right of the bullseye, you would choose the 35.0 grain charge as your OCW (optimal charge weight). This charge will allow 34.7 and 35.3-grain charges to the group. This will be a significantly “pressure tolerant” or “resilient” load.
18. Remember, do not get “bowled over” by a tiny group outside the OCW zone. You can tune any groups to be small with bullet seating depth changes. After you have determined the OCW, you may want to try seating the bullets deeper or longer in .010″ increments to see where your rifle does its best. If you are a real stickler for accuracy, you can do another “round robin” test using varied seating depths, perhaps in .003″ increments. Look for at least two seating depth stages that hit the same POI and group tight. I have often found that OCW recipes are so dependable that seating depth alterations, especially for game-hunting cartridges, are usually unnecessary.
19. Your next step would be to confirm that your load recipe is within the maximum range you will expect to use it. Load one round about 1% below and another about 1% above the OCW charge and fire a three-shot group with these two charges plus the standard charge at the maximum range you will require the load to be accurate. You should note MOA or be close to MOA grouping.
20. The OCW load development plan works best with rifles and shooters with MOA accuracy. If your rifle has not shown a propensity for reasonable accuracy, you should have it corrected before wasting time and material with additional load development. If you are not confident that you are at a level where you can shoot consistent MOA groups, you may want to hold off on intricate load development until your skills are better honed. Lots of practice with a scoped .22 LR is invaluable…
21. I recommend using shooting glasses during ANY load testing firing sequences. You can never be too careful here. And please know that you are on your own when you embark on load development. Like any provider of load data or development instructions, I must mention that I accept no responsibility whatsoever for any occurrences outside your expectations.