MV AND CHRONOGRAPHING
Muzzle Velocity is a function of powder charge, all other things being equal. More powder makes more MV.
The relationship, over some area, is kinda linear. Linear relationships, equations, are defined by the slope of the line and the height of the line above zero.
The slope, the angle up, is similar, for the lines in the two graphs shown in the post: MUZZLE VELOCITY VS. GRAINS OF POWDER.
I suspect that this slope is a characteristic of the powder, Titegroup in this case-I don’t know.
The chronographing goal for this testing was 12, now 13 measured shots. Collecting data carries a price, in my case the chronographing affects accuracy-that’s the price.
A sample size of 25 or 30 makes a better estimator of MV than samples of 12 or 13. There are 3 bullets, 7 powder charges and 10 barrels being investigated.
But.
If we assume that the slope is constant, and if sample size = EX 30, then we can measure MV for 30 shots at, say, 8.5 gr Titegroup, apply the slope, and get good estimates of MV at each charge from 5.5 to 8.5 gr Titegroup.
The 7 charges from 5.5-8.5 gr X 13 = 91 shots chronographed; vs. the 30 EX above.
Or, 30 @ 5.5 gr and 30@ 8.5 gr. Or 20@ 5.5 gr, 20@7 gr, 20@ 8.5 gr. 60<91.
If we know the slope, we can increase chronographing accuracy and reduce the number of shots measured.
