Reloading Velocities
- Thread starter ebruder
- Start date
Mystic Precision
CGN Ultra frequent flyer
- Location
- Summerland, BC
If you look at the chronie instructions, they used to indicate the error rate on the clock used to determine your speeds. I would only assume this is typical of most chronies.
The error is 1/2 of 1% so at 3000fps, the error in the chronie is +/- 15fps or more then the numbers you are trying to crunch.
I am not saying chronies are bad or have no purpose. Just don't take the number on the screen as gospel.
I use my chronie to determine where abouts I am in pressure during load development. There is no free lunch so if my speeds are way higher then expected, I am running hot and need to back off.
To determine what is a good load, I do my testing at 200yds and 300m. Any vertical issues is going to show up like a great big neon sign. Also, small changes in powder for tuning will also show up on the target.
At 300m, things get real obvious.
If you visit my website and look in the tech section, I have articles on load tuning for LR shooting. They have worked for me on dozens of rifles in cases from the 223 to the 300RUM. Also, seem to be helping a fair share of shooters get dialed in.
Hope this helps...
Jerry
The error is 1/2 of 1% so at 3000fps, the error in the chronie is +/- 15fps or more then the numbers you are trying to crunch.
I am not saying chronies are bad or have no purpose. Just don't take the number on the screen as gospel.
I use my chronie to determine where abouts I am in pressure during load development. There is no free lunch so if my speeds are way higher then expected, I am running hot and need to back off.
To determine what is a good load, I do my testing at 200yds and 300m. Any vertical issues is going to show up like a great big neon sign. Also, small changes in powder for tuning will also show up on the target.
At 300m, things get real obvious.
If you visit my website and look in the tech section, I have articles on load tuning for LR shooting. They have worked for me on dozens of rifles in cases from the 223 to the 300RUM. Also, seem to be helping a fair share of shooters get dialed in.
Hope this helps...
Jerry
It does depend to a certain degree on the quality of the chrony, and where your shots fly over the sensors.
the "Chrony" models have a hinge in the middle. If there is any defect in how that chrony sits on the tripod, the sensors will either point towards each other or away from each other to a very small degree. This means that the distance between the sensor paths will be different a the diffuser height than they will at the sensor height, and velocities will be reflected as such.
Keep your shots as low as you can in relation to the chrony, so they stay as close to the sensors as possible. If your chrony is crooked at ALL, the velocities will be inaccurate and es/sd numbers will be all over the place. keep the shots low, and the results will be more consistent.
I tend to look at the results, not the numbers.
the "Chrony" models have a hinge in the middle. If there is any defect in how that chrony sits on the tripod, the sensors will either point towards each other or away from each other to a very small degree. This means that the distance between the sensor paths will be different a the diffuser height than they will at the sensor height, and velocities will be reflected as such.
Keep your shots as low as you can in relation to the chrony, so they stay as close to the sensors as possible. If your chrony is crooked at ALL, the velocities will be inaccurate and es/sd numbers will be all over the place. keep the shots low, and the results will be more consistent.
I tend to look at the results, not the numbers.
- Location
- In the clock tower!!
I agree. My chronie is not the most expensive, but its up there. Every load I have tested in every rifle I have owned has not produced reliable tables when the values were entered in balistic programs. My personal chronie appears to be a bit low on acutal velocity (hence the results on the balistic programs). My buddies is way fast. Don't bet the farm on the numbers you see.
As Mystic and Obtunded said. Use as a guide and work off the acutal results at distance. (Shooter input on the rifle removed) this will be your best indicator of how your doing with your load.
As Mystic and Obtunded said. Use as a guide and work off the acutal results at distance. (Shooter input on the rifle removed) this will be your best indicator of how your doing with your load.
