You see, we shoot wax bullets powdered by shotgun primers. We certainly can't control the charge, we're reliant completely on the quality control of the primer manufacturer. We don't generally cast our own bullets, mainly because the various manufacturers keep it inexpensive enough that it's easier to buy the bullets than to make them at home. And, we're not really seeking extreme accuracy, but our hits are counted on the basis of time.
At sanctioned shoots, we control nothing about out ammo; it's supplied by the host and we have to trust that the loader knows his craft. So far, it's proved adequate.
But, there are still things we wonder about, so there are still things we can measure. This morning, I determined to find out some things about my ammo, the ammo I make myself at the house, so I set up my chronograph to find out a few things.
For the record, the temps were 84F, winds negligible, the pressure was 30.02 and humidity was 75%. My range is 122 feet above sea level. It was a standard, Louisiana summer morning.
My ammo was CFDA brass, Deadeye Easy-Loader bullets, and Rio 209 shotgun primers. All velocities were measure across a Shooting Chrony Alpha Master chronograph. Both at the muzzle and at 20 feet. I wanted to see how the velocity dropped off as the bullet approached the target.
The revolvers were both Ruger Vaqueros, one with a 4.62" barrel and one with a 7" barrel.
Below is the data. Please forgive my puny table-making skills.
Short Gun Long Gun Muzzle 20 feet Muzzle 20 feet
Hi 754.7 586.1 754.2 568.7
Lo 695.0 520.1 597.9 513.1
Avg 729.7 559.8 686.8 555.7
ES 59.7 66.0 156.3 55.6
StDev 17.7 21.6 52.3 19.7
Fairly interesting results. I believe that I had one "short charge" primer. The vast majority of my muzzle velocities were well above 650 fps. But, there's that one LO for the long gun at 597.9 fps. It's an outlier and skewed my AVG, ES, and StDev for that sting. If you look at the two 20-foot AVG between the short gun and the long gun, you'll see that they're within 4 fps of each other. Not much difference in velocity at all, but that little wax pill has lost a lot of velocity between the muzzle and the target, 21 feet away.
If you look at the Hi's between the short gun and the long gun, you'll see that they're within a half fps. You'd think that the long gun and the short gun would have a significant difference show up between the barrel lengths, but that doesn't seem to be the case.
I'll have to ponder this some more.