Re: Oehler Velocity readings?
The screens use two stop screens and one start screen to get the two chrono readings. Here's how they work;
The first screen the bullet passes over starts both chronographs, the second screen stops the PROOF chrono and the third screen stops the MAIN chrono.
The MAIN crono reading is the column to the right on the printer which all the other data is derived from, the PROOF chrono reading is on the left side and stands alone... no other data is calculated from this chrono reading.
The MAIN chrono's accuracy is better than the PROOF because the screen spacing is 4' rather than that of the PROOFS 2'. The proof will detect large errors and help you to keep your sanity in check. [img]images/icons/grin.gif[/img]
I use the Oehler 43 mainly and it converts it to MV with the distance to the screen I type in. The 35 needs to have the velocity loss added back in for the distance the MIDDLE screen is set away from the muzzle. If I'm nailing down an average MV for a load to use at LR in a ballistic program, I'll get that specific. The 43 is always MV though, so it's not an issue.
Here's what to do;
Velocity loss in 100 yards with your load divided by 300' will give you the velocity loss per foot you need to figure what the MV is for the muzzle to screen distance in feet you use. A ballistic program will tell you the loss at 100 yards.
At 3000 fps the 4' screens will be within 4 fps of actual, the 2' screen spacing will be within 8 fps. 1' would be 16 fps and likewise 8' would be 2 fps.
Good luck and enjoy! [img]images/icons/smile.gif[/img]