Gedro
Newbie
I ordered a magneto speed several months back and wanted to know how accurate it was so I set up a test with the 3 top types of chronographs. Here is the test and the results.
First, by types of chronographs I mean sight, acoustic, and magnetic. They each have their places.
-Magnetic can read supersonic and subsonic velocities but the unit is attached to the end of the barrel thus affecting barrel harmonics and possible accuracy. It can be used in light or darkness. Wind does not affect its readings.
-Sight or Picture chronographs have an advantage over the magnetic variety because they are set up usually 10 ft from the muzzle. Meaning that there are no effects on barrel harmonics or accuracy. They can measure supersonic and subsonic rounds. The downfall of these units is that sometimes light can affect the camera or sensors causing differences in readouts.
-The acoustic chronograph measures the distance of the cone or shock wave that travels in front of a supersonic round. These units are not able to detect subsonic rounds. This technology is pretty new as well.
The 3 units that I tested are the Magnetospeed V3 (magnetic), the Oahler 35p (sight or picture), and the Steinert Super Chrono (acoustic).
The test was set up to eliminate as many variables as I could think of. In order to eliminate ammo differences, this test was shot across all 3 chronographs at the same time. Basically, I attached the magneto speed to the barrel, then set up the Steinert acoustic chronograph to avoid any acoustic shadowing that may be caused by putting it after the Oahler. Then, I set up the Oahler 35p directly in line and after the acoustic chronograph.
I then shot 2 20 shot strings across all 3 chronographs consecutively. One 20 shot string with a identical charge of powder A and another with powder B. Here are my results.
As you can see, the Magnetospeed and the Oahler 35p ran neck and neck throughout the entire test. I found this interesting because the magneto speed is attached to the barrel and the Oahler is about 11 feet in front of the barrel giving the bullet 10 feet or so to slow down. The Steinert is all over the place really. However, I did notice that for some reason, the last half of each shot string, it read a little closer to the other 2 chronographs. I spoke with the guy that lent me the Steinert and showed him these results. He said that the unit needs to be set up perfectly parallel to the barrel. I took much care in setting up this test as I always do so everything was parallel. Here is a photo of the barrel and the Steinert showing good parallel.
I am still waiting to meet with him and set up the test in a similar manner to whatever specs he would approve of.
In conclusion, I would not hesitate to use either the Magneto speed nor the Oahler 35p. If the crappy numbers from the Steinert had to do with the set up, then I don't think it is a unit that the average Joe would be interested in using because of how precise it needs to be set up. This set up alone took me an hour and a half. If a guy wants to go out and get some numbers on his loads, taking a hour to set up the acoustic chronograph to make sure that everything is perfect is less than desirable. The proof is in the numbers here. While none of this might matter to someone who shoots issued rounds at human silhouette targets within 300 yards, it does matter in the LR world of precision. The bullet never lies and that is the ultimate test of gathering DOPE. However, as a hand loader, if you can not get your ES within 10% of your MV and your SD within 10 fps, then it will be hard to compete in any of the national LR games. Getting these numbers tells you how good you are doing your job at eliminating all of the reloading variables. Once you have them eliminated, load em up and shoot em!
First, by types of chronographs I mean sight, acoustic, and magnetic. They each have their places.
-Magnetic can read supersonic and subsonic velocities but the unit is attached to the end of the barrel thus affecting barrel harmonics and possible accuracy. It can be used in light or darkness. Wind does not affect its readings.
-Sight or Picture chronographs have an advantage over the magnetic variety because they are set up usually 10 ft from the muzzle. Meaning that there are no effects on barrel harmonics or accuracy. They can measure supersonic and subsonic rounds. The downfall of these units is that sometimes light can affect the camera or sensors causing differences in readouts.
-The acoustic chronograph measures the distance of the cone or shock wave that travels in front of a supersonic round. These units are not able to detect subsonic rounds. This technology is pretty new as well.
The 3 units that I tested are the Magnetospeed V3 (magnetic), the Oahler 35p (sight or picture), and the Steinert Super Chrono (acoustic).
The test was set up to eliminate as many variables as I could think of. In order to eliminate ammo differences, this test was shot across all 3 chronographs at the same time. Basically, I attached the magneto speed to the barrel, then set up the Steinert acoustic chronograph to avoid any acoustic shadowing that may be caused by putting it after the Oahler. Then, I set up the Oahler 35p directly in line and after the acoustic chronograph.
I then shot 2 20 shot strings across all 3 chronographs consecutively. One 20 shot string with a identical charge of powder A and another with powder B. Here are my results.
As you can see, the Magnetospeed and the Oahler 35p ran neck and neck throughout the entire test. I found this interesting because the magneto speed is attached to the barrel and the Oahler is about 11 feet in front of the barrel giving the bullet 10 feet or so to slow down. The Steinert is all over the place really. However, I did notice that for some reason, the last half of each shot string, it read a little closer to the other 2 chronographs. I spoke with the guy that lent me the Steinert and showed him these results. He said that the unit needs to be set up perfectly parallel to the barrel. I took much care in setting up this test as I always do so everything was parallel. Here is a photo of the barrel and the Steinert showing good parallel.
I am still waiting to meet with him and set up the test in a similar manner to whatever specs he would approve of.
In conclusion, I would not hesitate to use either the Magneto speed nor the Oahler 35p. If the crappy numbers from the Steinert had to do with the set up, then I don't think it is a unit that the average Joe would be interested in using because of how precise it needs to be set up. This set up alone took me an hour and a half. If a guy wants to go out and get some numbers on his loads, taking a hour to set up the acoustic chronograph to make sure that everything is perfect is less than desirable. The proof is in the numbers here. While none of this might matter to someone who shoots issued rounds at human silhouette targets within 300 yards, it does matter in the LR world of precision. The bullet never lies and that is the ultimate test of gathering DOPE. However, as a hand loader, if you can not get your ES within 10% of your MV and your SD within 10 fps, then it will be hard to compete in any of the national LR games. Getting these numbers tells you how good you are doing your job at eliminating all of the reloading variables. Once you have them eliminated, load em up and shoot em!