Crashbox
Member
Today I went out and tested my regular .357 Magnum paper-punching rounds using Herco, Missouri Bullet 140 TCFP and Federal 200 magnum primers. What I found was interesting.
The extreme spread was quite large, even with individually-weighed 7.5gn charges (131 FPS). And out of 30 rounds each, the standard deviation was 30 FPS weighed, 41 FPS with thrown charges. HOWEVER, when the first round of each cylinder-full is omitted (GP100 4" six-shooter), the standard deviation drops by about 40%; 24 FPS and 23 FPS, respectively. This is telling me something is going on with the first round, and I suspect it is because this powder is position-sensitive. I tend to tilt the revolver toward the ground when loading which will move the powder toward the bullet. After the first round, however, the powder is most likely pushed back toward the case head due to recoil. The two times that I made an effort to load with the firearm tilted somewhat upward revealed a first shot that was notably more consistent velocity-wise with the others.
Running them at 8.0gn of Herco revealed a similar trend, though my sample size was only 20 rounds.
I also shot 15 rounds of .405 Winchester ammo in my Ruger 1-H Tropical using 56.0gn of Reloder-15, Hornady 300gn FP Interlock #41050 bullet and Federal 210 primers. An extreme spread of 114 FPS (1967 to 2081 which is rather anemic IMO) and a SD of 35 FPS. Methinks this is not the best combo for this particular rifle.
A few days ago I clocked seven rounds of .405 using 57.0gn of IMR 4320 with other components identical and the ES was only 34 FPS (2161 to 2195) and SD was 12 FPS. It must be noted that I definitely need a larger sample size of this combo before I can draw any conclusions, but the preliminary data is not too shabby. Weather was virtually identical for both days.
In sum, I certainly have some more work to do, especially with .357/Herco. I think switching to regular primers will likely bring the ES and SD down, but we'll see. Like any tool, a chronograph can be very useful if the resultant data is applied properly. And I just LOVE my Oehler 35P.
This is fun.
The extreme spread was quite large, even with individually-weighed 7.5gn charges (131 FPS). And out of 30 rounds each, the standard deviation was 30 FPS weighed, 41 FPS with thrown charges. HOWEVER, when the first round of each cylinder-full is omitted (GP100 4" six-shooter), the standard deviation drops by about 40%; 24 FPS and 23 FPS, respectively. This is telling me something is going on with the first round, and I suspect it is because this powder is position-sensitive. I tend to tilt the revolver toward the ground when loading which will move the powder toward the bullet. After the first round, however, the powder is most likely pushed back toward the case head due to recoil. The two times that I made an effort to load with the firearm tilted somewhat upward revealed a first shot that was notably more consistent velocity-wise with the others.
Running them at 8.0gn of Herco revealed a similar trend, though my sample size was only 20 rounds.
I also shot 15 rounds of .405 Winchester ammo in my Ruger 1-H Tropical using 56.0gn of Reloder-15, Hornady 300gn FP Interlock #41050 bullet and Federal 210 primers. An extreme spread of 114 FPS (1967 to 2081 which is rather anemic IMO) and a SD of 35 FPS. Methinks this is not the best combo for this particular rifle.
A few days ago I clocked seven rounds of .405 using 57.0gn of IMR 4320 with other components identical and the ES was only 34 FPS (2161 to 2195) and SD was 12 FPS. It must be noted that I definitely need a larger sample size of this combo before I can draw any conclusions, but the preliminary data is not too shabby. Weather was virtually identical for both days.
In sum, I certainly have some more work to do, especially with .357/Herco. I think switching to regular primers will likely bring the ES and SD down, but we'll see. Like any tool, a chronograph can be very useful if the resultant data is applied properly. And I just LOVE my Oehler 35P.
This is fun.
