Re: Ballistic FTE problem?
How I use FTE:
A) Establish zero and related conditions at zero.
1) Use a tape measure to set the chrono at 10' in front of the muzzle
2) Record atmospheric conditions - Temp / Baro / RH / Alt / DA / Time / Lighting Conditions / Wind Conditions / Sight Height
3) Use an average of 20 rounds (not less than 10 rounds) to determine velocity.
B) Record all of this data as my zero data.
C) Use JMB to make a dope card based on this zero data - at least I have a rough guide to fall back on. (Bonus points if you tape it to your rifle.)
D) On site - obtain atmospherics by using a Kestrel or an Adaptive Consulting DA card and related implements.
E) Inputs:
- BC for a 175 SMK is .243 (G7)
- Diameter = .308
- Weight = 175
- Native Drag - G7
- Velocity is that 20 rnd average from your zero
- Chrono dist - what you measured when you zeroed
- Use Drag = G7
- Range Zero - what distance you are zeroed for
- Sight Height - what you have previously measured and recorded
- Y-intercept = 0
- LOS Angle = 0
- Zero Atmosphere = 'Enable' and enter DA from Zero Data
- Current Atmosphere = 'Enable' and enter on site DA
- Wind Velocity = 10
- Wind Angle = 90
- Wind Position = Muzzle
- Upwind Velocity = 0
- Max range = User Defined
- Range increment = User Defined
- Vital zone Radius = Factory Setting
- Elevation Unit = MRAD
- Wind Unit = MRAD
- Spin and Stability = Off
- Coriolis Acceleration = off
Using this method I am typically given info that is within 0.2 MILs of being spot on. Regardless, when I give the correct inputs, it will always spit out an elevation result that will put me on a 26"x19" IPSC out to @ 1,200 - if I make the right call on wind. (After 1,200 if I am holding COM and the calc'd error is 0.2 MILs I run the risk of missing the target - as always it is critical to spot your own misses).
Good luck
