Ok, I am about to take the plung and get a chronograph. I know I definely want a printer so I can take the printer tape, tape it to my targets and have a permenent record (until I lose my range notes). Here is the question. When testing new loads how many shots do you need to have useful statistical informtion? Is ten enough, 12,15,20? what seems to be the standard here? Thanks for the info. Peace!
Everything I know about BPRC I have forgotten at least three times, Now I write it down. Have you seen my note book?
From the standpoint of simple statistical analysis of your bullet velocities a 5 shot group is probably sufficient. Typically, a series of chronographed shots from many of these black powder/cast bullet rifles (either breech or muzzle loaders) have very low standard deviations such that 10 shots really doesn't add a great deal to knowledge that 5 shots showed. Standard deviation is a statistical parameter that measures the amount of shot to shot variation in bullet velocities for a group of shots. However, there is nothing wrong with more shots, if you so desire. Additionally, if you want you could test to see if there is a statistical difference in velocities between 5 or 10 shot groups or whatever. Many of the pocket calculators available now have a whole series of statistical analyses programmed into them. A good simple analysis for this type of data would be Student's "t" test; an easy test to conduct to determine if significant differences exist in velocities between your 5 shot or 10 shot groups.
However, if you are an avid silhouette competitor, then you may very well want to shoot 10 shot groups as your standard to determine average group sizes and velocities. This would give you a good read on what to expect in a bank of silhouettes for the weather conditions at the time you conducted your test. For instance, if your velocities for the 1st 5 shots are really close, but the next 5 shots the velocities start to jump around some you will likely need to know this. This may indicate you need to do more blow tube work or maybe more lube work or maybe whatever. Additionally, it would be best to conduct your tests in weather (at least temperature) you at least expect to encounter during the time of your competitions.
A hunter on the other hand could likely care less about the 10th shot in a series of shots; his main concern is the 1st shot and maybe the 2nd shot just in case moby buck still has both oars in the water after the 1st shot and is trying to get his feet under him again. He also should conduct his tests in weather conditions that he expects to encounter at the time of the hunting trip.
I have created a Excel spread sheet that does all the fancy calculations for you. You can insert rows and calculate ES, SD and all the other functions you want for any number of shots.
All you need do is print out the file and record the velocities while at the range, then at home enter the velocities in the spread sheet and it does all the work.
Since you want a printer, you may want to look at the Oehler 35P. It gives you both an LED read out and a paper roll print out. Another reason I got it is I like having the sky screens separate from the electronics. This way the electronics are up close to me for easy read out, but more importantly I am shooting at the relatively inexpensive sky screens to replace it I inadvertently hit them and not at the expensive electronics. Also, the three sky screen set up gives you a positive check that you've gotten a good reading.
Ok, I am about to take the plung and get a chronograph. I know I definely want a printer so I can take the printer tape, tape it to my targets and have a permenent record (until I lose my range notes). Here is the question. When testing new loads how many shots do you need to have useful statistical informtion? Is ten enough, 12,15,20? what seems to be the standard here? Thanks for the info. Peace! 
