I have a BSA 7mm with a Bushnell 4-12x 3200 Elite with AO and BDC. Since the range here does not go beyond 200 yds, setting up my scope to know what ranges the BDC lines truly represent is tough. I am shooting Federal Premium Vital-Shok 160 gr Nosler AccuBonds. The scope is supposedly set up for 150 gr for the 7mm at 100 yd zero, but I wanted to stick with 160 gr at 200 yd zero. I went to the range yesterday and sighted in my gun for zero at 200 yds. My question is this. The trajectory chart that Federal provided online show a zero at 200 yds and -39.9 inch bullet drop at 500 yd for my exact bullet. Pivoting that trajectory curve from the muzzle to have it hit a horizontal line at 300, 400 and 500yds, I get almost equally spaced elevations above the 200 yd bullseye of about 4-1/2" for the 300 yd shot. Another 4-1/2" higher again for the 400 yd shot and still another 4-1/2" higher for the 500 yd shot. Based on this, if I aim 13-1/2" above the bullseye on the 200 yd range my bullet should hit a horizontal mark at 500 yd. You with me? Now, since the scope's BDC lines never fall on even 100 yd increments anyways, can I just hold each of the lines on the 200 yd bullseye and then measure how high each line shoots above the bullseye. Then interpolate on the trajectory chart to determine what range each of the BDC lines represents. Any ideas out there?
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