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The way I order the critical factors is this:
1. The ammo
2. The rifle
3. The consistency of the conditions
4. The skill of the shooter
The critical factors and the order in which they are placed has been argued before, and to a certain extent is an opinion of the correspondent. Please take it to another thread if you wish to argue about it.
You've asked about case prep, that's what I'll cover. Bullet preparation is something else, if you've got a consistent lot you won't have to do anything, and I'll assume the bullets are consistent and/or sorted.
This is also sorted by the amount you'll have to spend for tools, because if you want to shrink your groups, you have to be able to measure the results of your efforts.
To go from 1 MOA to 0.5 MOA or better, do the following:
1. Starting with new, quality brass, and do the primer pockets, flash holes, trim to length, size and champher.
2. If you can, measure the neck wall thickness at several places on the neck, setting aside anything with greater than 0.0015" variance for practice.
3. After this, weigh the cases and sort into 0.5 gr. groups. Go to step 7.
4. After you've fired the brass, clean it in a tumbler, remove the primers, clean the primer pockets.
5. Inspect the cases, and set aside any with an obvious balloon to one side of the case or banana shape for practice.
6. Size the brass with either a full length or neck sizing die.
7. Trim to length and chamfer.
8. Seat the primers with a hand priming tool.
9. Weigh your power charges or use a quality thrower.
10. Use a standard seating die to seat the bullet.
11. Test primer, powder and seating depth combinations for best groups.
To get 0.25 MOA or better, do the following:
1. Follow steps number 1 and 2 above for new brass.
2. Neck-turn the remaining brass, setting aside the brass which didn't have any valleys. This is keeper match stuff. Use it for longer distances, etc. Make sure you trim far enough into the shoulder to avoid donuts, anywhere from 0.010" to 0.030", depending upon the brass and the cutting angle at the shoulder end of the neck turning tool.
3. Neck turn the brass again after letting it rest for a day or two.
4. Your goal is a neck case variance of less than 0.0003".
5. Clean and polish the cases.
6. After this, weigh the cases and sort into 0.5 gr. groups.
7. Seat the primers with a hand priming tool.
8. Weigh your powder charges to +/- 0.1 gr. on a quality scale. Be aware of how your scale functions in terms of settling, sensitivity, and grain size/shape of the powder.
9. Using a quality seating die, seat the bullets to +/- 0.001, measured at the ogive.
10. Rotate the case 120 or 180 degrees as you are seating the bullet, I would recommend the use of a qualtiy seater, and keep the length tolerance at the ogive to +/- 0.001".
11. Test each round for concentricity. The goal is 0.0015" TIR at the ogive measurement point.
12. For fired brass, deprime and clean the primer pockets with your uniformer.
13. Clean the brass with Iosso, Birchwood-Casey Case cleaner, or your buddies favorite mystery combo of Simply-Green, lemon juice, Dawn, etc. Then finish clean and polish in a tumbler with corn cob and a quality polish.
14. Neck size or full length the cases with a quality die which uses a neck bushing to control neck tension. Every diemaker screws up occasionally, so if you have problems, check with another die. Figure out what neck tension works best with your load; this is another variable to test when checking which primer, powder, and seating depth works best. Again, put any cases with a balloon to one side or banana shape aside to use for practice.
14. Neck turn the brass again if once fired, you shouldn't have to repeat this step again until you have ten or more firings on the case.
15. Trim to length an chamfer.
16. Clean to remove lube, and polish the brass again.
17. Seat a primer in the case, rotating the case 120 to 180 degrees to ensure the primer isn't seated to one side of the pocket.
18. See steps 8, 9, 10 and 11 of the 0.25 MOA instructions.
19. See step 11 of the 0.5 MOA instructions, adding a test for neck tension after the other steps.
Be aware of the effects of temperature on your load, reduce or increase the powder charge to maintain the best accuracy level. Always follow good reloading procedures; starting low and working up with powder charges, at least off the lands by 0.020" to start, seating the bullet deeper into the case by 0.005" can push a load over the edge.
General rules:
Keep the torque on the nut behind the trigger consistent and relaxed.
If firing a string of five or more shots, don't leave a round in the chamber longer than 45 seconds.
Learn the POI of the first three shots if shooting a long string, the tenth and higher shot in a long string seems to have a different POI, also.
YMMV, but it works for me. Are all these steps necessary? Absolutely not. Can you achieve under .5MOA accuracy without doing some of the steps? Of course, but with what consistency? Some of these steps I simply have found to be a total waste of time and I consider them being overly anal retentive. I've loaded 25 rounds of the same charge with some of the steps excluded and shot them in a series of 5 test (125 rounds total fired to rule out some variables) and found some steps really offer very little gain. It really boils down to how much you enjoy it and how much better it makes you sleep at night or feel on match day. I like to have 100% confidence that every round in my box is as consistent as I can possible make them.
Hope this information helps someone out there.
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