AGD, All - Finally can chrono 10+ BPS and more!!!

[cledford]

All,

A while back I made the following post regarding the chronographing of shot strings in the 10BPS range and up. The link to my previous post is:

http://www.automags.org/forums/showthread.php?s=&threadid=22430

[email protected].

-Calvin

[manike]

I wonder if they do mail order...?

Does it also give you the time between shots? or is just giving you a list of velocities?

If you got the time between shots as well and then could relate that to the velocities it would be very interesting and I see limitless experiments on the horizon... :)

manike

[cledford]

[cledford]

[cledford]

Standard

If you look closely at the output above - there are 2 numbers per line. (Sorry I could have made it easier to read if I'd put tabs in each line...) The first is the velocity, the second is the Standard Deviation from the then entire 18 shot group average velocity. Standard deviation is very cool, here is a write up that explains it. The information came from the product manual for the CED chronograph.

-Calvin

Standard Deviation - Based on the universal mathematical equation for uniformity, this function uses
all the data entries in a string to calculate the Standard Deviation of the combined shots / velocities in
that string. The larger the number of data entries in the string, the more accurate the SD becomes. The
CED Millennium requires a minimum of 5 shots / velocities to be received in order to calculate SD.
However, it should be noted that the more data entries used in SD calculations, the more reliable the SD
will actually be. Statisticians usually recommend 20 shots / velocities for the best reliable results. Edited
or omitted entries will not be included in SD calculations.
Standard deviation is very confusing to many people and as such, is not often used. However, in reality,
it is the best textbook measure of velocity uniformity available and when used properly and in conjunction
with other load data will give very meaningful results. Average velocity has been the standard for
years. However, it does not indicate how much the velocities being measured varied above and below
the average. The standard deviation actually measures how close each shot velocity will be to the
"average". The more uniform you can make the ammunition, the better the odds (no guarantees) that it
will produce the exact same results. The mathematical equation for standard deviation is extremely
complex and prior to electronic calculation (computers) it was seldom used by shooters. What it means
though, is that statistically, it has been proven that 68% of all things measured will fall between one
standard deviation above or below the average. Additionally, 95.4% will fall between two standard
deviations above or below, and 99.7% will fall between three standard deviations above or below the
average.

Example = If you have a standard deviation of 10 fps with an average velocity of 1000 fps, then you can
expect that 68% of the shots fired will fall within 990 fps to 1010 fps. Further, it can be determined that
95.4% of the shots fired will fall between 980 fps and 1020 fps and that almost all of the shots fired
(99.7%) will fall between 970 fps and 1030 fps.

[AGD]

Calvin,

Got your email and I have been monitoring this post. The problem here is that the paint varies pretty badly so unless you test multiple guns with the same paint on the same day it's hard to get a feel for what is gun and what is paint. In the shop we shoot nylon balls that are very round. It is not uncommon for us to shoot the same velocity within tenths of a fps for several shots. This is VERY rare when shooing real paint.

Pull up several guns and crono them at full speed with the same paint and post the results.

AGD