cobra 1,
Congratulations, you get a Gold Star for your powers of observation. I was wondering if anyone would notice the discrepancy. Thank You.
Since this wasn’t a laboratory test done in a wind tunnel with every variable meticulously documented and accounted for, there will be a range of uncertainties in the results. Here are just a few of the items that will skew the results:
1. I used a card table because I didn’t want to move my concrete shooting bench or a portable bench into the middle of a field. While it’s possible to shoot very small groups off a card table, it’s neither fun nor easy.
2. I tried to set up with the wind perpendicular to the course of fire, but it often varied by as much as 30 deg’s.
3. I wanted to alternate each shot between the two targets, but figured I’d run out of time or get dizzy in the attempt. This would have averaged the wind’s variability much better than shooting first one target and then the second because the wind varied from an average on target #1 of 6.9mph with one recorded gust to 10.6mph, to target #2 with an average of 6.1mph with a recorded gust of 8.9mph and no attempt was made to dope the wind.
4. I wasn’t able to maintain my normal level of measurement precision because too many bullet holes were in the black on my scanned and digitized targets.
5. This test was at 25 yds instead of 50 yds and I’m not certain how or if that might change the results.
Most or all of these variables shouldn’t change the orientation of the ellipse on a clock face but would raise the uncertainties for calculating the mathematical center of each group and “that” would change the plane of the ellipse formed by the two groups.
If you factor in the range of uncertainties, then you can see that it’s possible my testing could have duplicated the predicted mathematical calculations or the actual testing done at the BRL (Ballistic Research Lab) in Aberdeen as reported in Document MR-3877 and if I would have repeated the test enough times to lower those uncertainties they would have most probably changed my results too.
Landy
