I was testing out the new chrono and I put together the following data. The fragmentation velocities are from the previously posted fragmentation chart
www.ar15.com/forums/topic.html?b=3&f=16&t=189353I have no way to verify them so if they are incorrect, let me know.
I used an online ballistics calculator to get the predicted fragmentation range from the measured velocity:
www.eskimo.com/~jbm/ballistics/traj_basic/traj_basic.htmlThe chrono was 15ft from the muzzle and the temp was around 70 degrees.
Hornady TAP, 75 gr, 16 inch barrel, 1 in 9 twist
2590.0
2552.0
2557.0
2520.0
2513.0
2519.0
2529.0
Overall Avg Velocity 2540.0
Overall Max Velocity 2590.0
Overall Min Velocity 2513.0
Overall Avg Variance 77.0
Fragmentation Velocity from 223 fragmentation chart: 2300 fps
Fragmentation distance of min velocity: 100 yds
Fragmentation distance of avg velocity: 110 yds
Fragmentation distance of max velocity: 135 yds
Black Hills New - Red Box,75 gr,16 inch barrel, 1 in 9 twist
2551.0
2599.0
2613.0
2603.0
2552.0
2606.0
2527.0
2608.0
2555.0
2611.0
Overall Avg Velocity 2582.5
Overall Max Velocity 2613.0
Overall Min Velocity 2527.0
Overall Avg Variance 86.0
Fragmentation Velocity from 223 fragmentation chart: 2300 fps
Fragmentation distance of min velocity: 100 yds
Fragmentation distance of avg velocity: 125 yds
Fragmentation distance of max velocity: 140 yds
Black Hills Reman., 75 gr, 16 inch barrel, 1 in 9 twist
2579.0
2521.0
2582.0
2464.0
2568.0
2530.0
2531.0
2561.0
2524.0
2547.0
Overall Avg Velocity 2540.7
Overall Max Velocity 2582.0
Overall Min Velocity 2464.0
Overall Avg Variance 118.0
Fragmentation Velocity from 223 fragmentation chart: 2300 fps
Fragmentation distance of min velocity: 75 yds
Fragmentation distance of avg velocity: 105 yds
Fragmentation distance of max velocity: 125 yds
I also tested some XM193 for reference:
Federal XM-193, 55 gr, 16 inches, 1 in 9 twist
3053.0
3054.0
2984.0
3028.0
3052.0
3070.0
3073.0
3037.0
3079.0
3016.0
Overall Avg Velocity 3044.6
Overall Max Velocity 3079.0
Overall Min Velocity 2984.0
Overall Avg Variance 95.0
Fragmentation Velocity from 223 fragmentation chart: 2700 fps
Fragmentation distance of min velocity: 75 yds
Fragmentation distance of avg velocity: 90 yds
Fragmentation distance of max velocity: 95 yds
BH RB 75gr(23.00 per 50, 46cents/rd)
Hornady 75gr TAP (15.00 per 20, 37.5 per 50, 75cents/rd)
BH BB 75gr(20.00 per 50, 40cents/rd)
Check out this thread as well:
www.jobrelatedstuff.com/forums/topic.html?b=1&f=9&t=444423Based on the info above, I plan to start using more BH Red Box. It is only 6 cents more per round than the BH BB and had the best performance of the three 75gr rounds tested. I did an earlier test on the BH BB and it was much more variable. This time I removed the rounds with obvious case issues(dents, etc) and it did a bit better.