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Originally Posted by jatx
Sir,I did something earlier and added a 33 yard zero following Gene's post. Assumptions were as follows: 14.5" barrel 55 gr. Sierra FMJBT
Muzzle velocity 2861 fps Sight height 3.0 inches. I hope this helps. ETA: Axis labels got erased, but the vertical axis is inches of drop.
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JTAX:
My 33 yard estimate was about as close as I could get but in no way can I say it is perfect. It is probably within plus or minus three yards of my estimate though.
Try not to make assumptions unless you must. Those computer programs are not perfect by any means. Some emphasize trajectories to about 500 which gives error to ranges past 500. Others emphasize trajectories from 500 to 1000 at the expense of short range precision. Niether will give a perfect representation of what you shoot as ballistic coefficients change with speed. So there are errors involved. These programs will put you on paper at 600 -- generally within plus or minus 1 1/2 minutes. In other words they will give a nine ring elevation. At 1000 one must be on drugs to trust a PC ballistics program to give sufficient accuracy to have confidence a bullet will hit a six foot target frame. The problem is that the shooter doesn't know the time of flight of his particular load to 1000 unless he chronographs it at the barrel and then at 1000 enough times to trust his results.
One thing you should also watch closely is your perception of the path of a trajectory on your PC screen. Your trajectory must be exaggerated in order to show rise and fall on a short screen. It gives the user an illusion of a more parabolic path than the very flattened path found in reality. The computer programs are right, they just have to distort the trajectory to fit on a screen. Unlike the computer programs, shooting on KD ranges to see trajectory gives a very different picture. You will find that the bullet's rising branch is relatively steep for a short distance and then less steep to its ordinate. Past its ordinate it tends to drop relatively uniformly but not perfectly uniform, due to drag. It is really quite interesting to see the differences between reality and the graphics of a computer program.
Gene