At the range last Wednesday

[Sailman]

I went to the range last Wednesday to do my final preparation for our annual State Championship Military Bolt Action Rifle Match. In previous trips to the range I had narrowed the selection of loads for the 30-180-SP bullet to powder charges of 4227 from 15 gr. to 18 gr.

Before I go any further, I should tell you how I record my groups.
20 ( 2 1/2 H X 3 V ) 20- G- 3 indicates that I shot a 20 round group that measured 2 1/2 inch horizontal by 3 inch vertical and it measured 3 inch diagonal.

In addition, 20 [ 18 ( 2 1/2 H X 2 7/8 V ) 20 ( 2 1/2 H X 4 1/2 V ) ]
18-G-3 indicates that I shot a 20 round group of wihich 18 rounds measured 2 1/2 inch horizontal by 2 7/8 inch vertical AND the 20 rounds measured 2 1/2 inch horizontal by 4 1/2 inch vertical and, 18 rounds measured 3 inches diagonal.

I like to shoot a 20 shot group because in basic statistics the greater your sample size the more realiable your prediction of results.

The following are the results of my tests at the range:
15 gr. 4227 20 ( 3 3/8 H X 2 3/8 V ) 20-G-3 1/4
16 gr. 4227 20 ( 2 1/2 H X 3 V ) 20-G-3
17 gr. 4227 20 [ 18 ( 2 H X 1 7/8 V ) 20 ( 2 1/2 H X 2 7/8 V ) ]
18-G-2 1/8
18 gr. 4227 20 ( 3 1/8 H X 2 1/2 V ) 20-G-3 1/4

Based upon the above data I have selected the 17 gr. load for the
30-180-SP bullet to shoot in the match.


Sailman

[felix]

Sailman, if your a statistical man, then shoot 30 round groups. The reliability goes up to 99 percent. ... felix

[sundog]

Whatever Sailman was doing, it worked for him on Saturday as he bested my 290 by 4 (both of us had 6X). Good job! I know the top four from my club were shooting cast. We came in second with 1447/1500-29X. The winning individual had both small group, 1.498, and high agg, 298-10X, but he [I'm pretty sure] was using heathen bullets. Fun was had by all! sundog

[sundog]

Felix, we shoot this match starting with a SR-21, and then we overlay a center (SR-21C), one at a time, shooting 2 groups, then 3 scores. When finished, the sighter is a composite of 50 record rounds, plus sighters. Gives a VERY GOOD picture. sundog

[Buckshot]

............Sailman, good job and congratulations. An interesting and sensible way to keep track of your groups. I appreciate your sharing that.

...............Buckshot