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| Hdspace | SPOAL | Powder | Round | X off | Y off | X | Y | Group | Vertical | Measured group calculation | ||||||
| -0.0020 | 1.887 | 21.0 | 1 | 2.5 | -110.0 | 0.10 | -4.33 | 1.47112 | 1.44 | 0.386749 | 1.471116 | 1.08482 | ||||
| -0.0015 | 1.890 | 21.2 | 2 | 0.0 | -100.5 | 0.00 | -3.96 | 1.08482 | 1.06 | 1.08482 | 0.65436 | 0.640292 | ||||
| -0.0015 | 1.889 | 21.4 | 3 | -5.5 | -73.5 | -0.22 | -2.89 | 0.83051 | 0.83 | 0.640292 | 0.830511 | 0.528937 | ||||
| -0.0020 | 1.888 | 21.6 | 4 | 6.0 | -85.0 | 0.24 | -3.35 | 0.66172 | 0.57 | 0.528937 | 0.661721 | 0.200748 | ||||
| -0.0020 | 1.890 | 21.8 | 5 | -3.5 | -94.5 | -0.14 | -3.72 | 0.78444 | 0.75 | 0.200748 | 0.585277 | 0.784442 | ||||
| -0.0020 | 1.888 | 22.0 | 6 | -2.5 | -99.5 | -0.10 | -3.92 | 2.02994 | 1.91 | 0.784442 | 2.029943 | 1.484881 | ||||
| -0.0020 | 1.889 | 22.2 | 7 | -8.5 | -80.5 | -0.33 | -3.17 | 1.48488 | 1.16 | 1.484881 | 0.783948 | 0.725947 | ||||
| -0.0020 | 1.889 | 22.4 | 8 | 15.0 | -51.0 | 0.59 | -2.01 | 0.72595 | 0.47 | 0.725947 | 0.65436 | 0.081163 | ||||
| -0.0015 | 1.889 | 22.6 | 9 | 1.0 | -63.0 | 0.04 | -2.48 | 0.31802 | 0.12 | 0.081163 | 0.237855 | 0.318021 | ||||
| -0.0020 | 1.890 | 22.8 | 10 | 3.0 | -62.5 | 0.12 | -2.46 | 1.29637 | 0.96 | 0.318021 | 1.020967 | 1.296373 | ||||
| -0.0020 | 1.890 | 23.0 | 11 | -4.5 | -65.5 | -0.18 | -2.58 | 1.29637 | 0.96 | 1.296373 | 0.897774 | 0.728345 | ||||
| -0.0015 | 1.890 | 23.2 | 12 | 17.5 | -41.0 | 0.69 | -1.61 | 0.75448 | 0.73 | 0.728345 | 0.19685 | 0.754478 | ||||
| -0.0025 | 1.888 | 23.4 | 13 | 17.5 | -59.5 | 0.69 | -2.34 | 0.75448 | 0.73 | 0.754478 | 0.713293 | 0.540532 | ||||
| -0.0020 | 1.887 | 23.6 | 14 | 12.5 | -41.0 | 0.49 | -1.61 | 0.69597 | 0.49 | 0.540532 | 0.69597 | 0.395664 | ||||
| -0.0020 | 1.889 | 23.8 | 15 | 26.0 | -43.5 | 1.02 | -1.71 | 0.96937 | 0.47 | 0.395664 | 0.810917 | 0.969374 | ||||
| -0.0020 | 1.889 | 24.0 | 16 | 25.0 | -53.5 | 0.98 | -2.11 | 2.16964 | 0.47 | 0.969374 | 1.280131 | 2.169641 | ||||
| -0.0020 | 1.888 | 24.2 | 17 | 46.5 | -41.5 | 1.83 | -1.63 | 2.16964 | 0.43 | 2.169641 | 1.102536 | 1.103941 | ||||
| -0.0025 | 1.889 | 24.4 | 18 | -7.5 | -52.5 | -0.30 | -2.07 | 1.46319 | 0.49 | 1.103941 | 1.463193 | 0.362973 | ||||
| -0.0015 | 1.890 | 24.6 | 19 | 18.5 | -42.0 | 0.73 | -1.65 | 0.72861 | 0.45 | 0.362973 | 0.728611 | 0.432174 | ||||
| -0.0020 | 1.888 | 24.8 | 20 | 27.5 | -40.0 | 1.08 | -1.57 | |||||||||
| -0.0020 | 1.890 | 25.0 | 21 | 33.0 | -30.5 | 1.30 | -1.20 | |||||||||
| Mean: | -0.0019 | 1.8889 | ||||||||||||||
| Min: | -0.0025 | 1.8870 | 
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Vertical group dispersion | ||||||||||||
| Max: | -0.0015 | 1.8900 | 0.37 | 1.44 | 1.06 | |||||||||||
| Spread | 0.0010 | 0.0030 | 1.06 | 0.61 | 0.45 | |||||||||||
| StdDev: | 0.0003 | 0.0010 | 0.45 | 0.83 | 0.37 | |||||||||||
| SP limit: | 1.907 | 0.37 | 0.57 | 0.20 | ||||||||||||
| 0.20 | 0.55 | 0.75 | ||||||||||||||
| 0.75 | 1.91 | 1.16 | ||||||||||||||
| 1.16 | 0.69 | 0.47 | ||||||||||||||
| 0.47 | 0.45 | 0.02 | ||||||||||||||
| 0.02 | 0.10 | 0.12 | ||||||||||||||
| 0.12 | 0.85 | 0.96 | ||||||||||||||
| 0.96 | 0.24 | 0.73 | ||||||||||||||
| 0.73 | 0.00 | 0.73 | ||||||||||||||
| 0.73 | 0.63 | 0.10 | ||||||||||||||
| 0.10 | 0.49 | 0.39 | ||||||||||||||
| 0.39 | 0.08 | 0.47 | ||||||||||||||
| 0.47 | 0.04 | 0.43 | ||||||||||||||
| 0.43 | 0.02 | 0.41 | ||||||||||||||
| 0.41 | 0.49 | 0.08 | ||||||||||||||
| 0.08 | 0.45 | 0.37 | ||||||||||||||
| Powder | Accurate AA2200 |
| Charge | 21.0 - 25.0 grains in 0.2 grain increments hand weighed |
| Bullet | 52 grain moly'd Sierra Matchking HPBT |
| Seating | 1.889" SPOAL (about 0.015" off the lands) |
| Primer | Federal GM205M (match primers) |
| Cases | LC weight sorted to the range 90.0-90.5 grains, and sized at -0.002 |
Note that both the overall group size and the vertical dispersion agree for AA2200. The smallest 3 round group is rounds 9, 10, and 11, with powder charges of 22.6, 22.8, and 23.0. Looks like I should evaluate a 22.8 grain load. These rounds are in red on the target chart. Interestingly, if you check the AA2200 Small Groups page you will see that the smallest groups occurred at 22.5 grains and then at 24.5 and 25.0 grains.
3 round groups are probably the most indicative in the Ladder Test, but looking at some 5 round groups is also interesting. It is important to remember that this target was shot at 200 yards. All 21 rounds, spanning 4 full grains of powder charge yielded a 3.35" group or less than 2 MOA. Remember too, that AA2200 is a fast powder. The overall vertical dispersion for 21 rounds of AA2200 was about half of the vertical dispersion for 21 rounds of Varget.
Groups of 5 consecutive rounds span 0.8 grains of powder. The 5 round group of 3, 4, 5, 6, and 7, yields a size of 1.02" or 0.5 MOA (average powder charge: 21.8 grains). The 5 round group, 12, 13, 14, 15, and 16, yields a size of 0.75" or 0.37 MOA (average powder charge: 23.6 grains).
To me this implies is that over short ranges, other factors swamp out small variations in powder charge, though, 0.8 grains is hardly a small variation! This also implies to me that this rifle is capable of astounding accuracy.
