There is a requirement for Wild Bunch shooting that the Power Factor for your ammo be at least 150 and that the maximum FPS be 100fps so I was experimenting with my loads to find one which met that criteria.
Power factor is determined by multiplying your bullet speed by bullet weight and then dividing by 1000. So my speed were measured at between 820 and 850fps. If I use my low speed that’s 820×200/1000 for a power factor of 164. That seems like a good number to stick with.
Unfortunately my Shooting Chrony took one (actually two) for the team today. Early on I had hit one of the posts so I had to fix that…no real damage there. I was having all sorts of problems getting the Chrony to read, I kept getting errors so I decided that I would aim closer to the sensors and see if that helped….it did. I got a reading, cool, shot again and got another but my third shot hit the Chrony and put a hole through it.
Bummer, I shot my chronograph and I still didn’t have a load figured out. I brought the damaged Chrony back into the shop and noticed that although it looked bad, the front photo sensor seemed to be intact. I didn’t know it it still worked but it looked like it could. I brought the setup out again and this time brought out a pistol rest to use….oh, didn’t I tell you that I was shooting one handed when I hit the device?
Using the rest I aimed about 6″ above the sensors and squeezed, bang! 850fps, bang! 820fps, bang! 842fps. Not only was the Chrony working but I was getting the first repeatable and reliable readings all day.
I called it success and packed up the kit and brought it back into my shop.
I’m going to call Shooting Chrony tomorrow and see how much they will charge to rebuild it and if it’s too much I’ll just use it like it is. Now it’s got character 🙂
Haven’t heard back from Shooting Chrony but I took a hammer to mine and straightened it out well enough so that it now folds up like it did in its pre-purple heart days.
Unless they come back with a low figure for repair I’m just going to use it this way as it is completely functional.
After doing some more research on the net I decided I’m going to use WST powder as it is not temperature sensitive like Clays and many of the Wild Bunch shooters use it.
It meters the same as Clays so all I had to do was change the powder and I was off and reloading.
I took my wounded warrior Chrony out for another round of testing before I load up a new batch of bullets which I cast from some 14.9BHN wheel weight lead. I fired 8 rounds and recorded 5. The spread was pretty large so I’m going to have to do it again and then adjust my loading procedure to tighten it up if I need to. I got
772, 801, 814, 826 and 879 which gave me an average of 818fps and a power factor of 163 which is almost exactly the same as I got with the Clays.