i put in 1:7 but i think there is only 2 lanz or groves in the smooth twist, i don't know for sure but the twist rate is probably much less. maybe a 1:4. i found out i had to come up with my actual B.C.,
Ah, ok - I'm not good with numbers. With 1:7 or 1:4, does that mean I would need to put either 4.0 inches or 7.0 inches in the Strelock field (Twist rate, inches per turn)?
Also, in order to work out my own BC like you have, I assume I would need to first purchase one of those chronometers? Their pretty expensive, any suggestions as to ones worth buying, or alternative ways to do the calculations in the AOA calculator?
I used the free app, Chrono Connect, for about a year before I got a chronograph. I found it to be pretty good as long as you set it up properly. It uses time and distance to calculate speed. I found it to be within 50 fps when shooting 650 to 900 fps.