What if I shoot several different bullet weights thru the same rifle?
You can purchase a TTC knob that is calibrated for your main load and adjust the knob for the other loads. For example, your knob was calibrated for the 308-168gr. Federal Match load and you want to also shoot your 150gr. Federal NBT load. You will have to subtract a set amount of clicks from each 50/100 yd setting. A 500 yard shot for the 150 gr. NBT would be to dial the knob to 500 yds then subtract (decrease yardage) 9 clicks. You can make up a simple chart for the 150gr. load: 100 yds -2 (clicks), 200 – 3, 300 – 4, 350 – 5, 400 – 6, 450 – 7, 500 – 9, etcﾅ
The preferred way is to have a second knob calibrated for the 150gr. load. This way you can swap knobs accordingly. You should keep a simple log that tells you how many clicks to subtract to re-zero the scope from the 168gr. 100yd zero to the 150gr. 100yd zero. For Example: Log entry: 150gr. 100yd zero = – 2 clicks down @ 100yds. (mount 150gr. knob and set at 100yds; – 2 clicks down, loosen setscrews, reset knob to 100yds, then tighten setscrews.)
Now you are ready to dial in and shoot the 150gr. load. The process would be reversed when you want to remount your TTC calibrated for the 168gr. load. (mount 168gr. knob, set at 100yds, +2 clicks up, loosen setscrews, reset knob to 100yds, then tighted setscrews)