When all is said and done, you need about 45 MOA to shoot at 1000 with the .308. If the scope starts with 51", then you only have 25.5" of up from the true zero of the scope. And as is mentioned above, the scope's true zero may require a lot of adjustments in either up or down. (due to manufacturing tolerances on the rifle and bases/rings). Some scopes (because of these variables) "may" not have enough MOA to zero at 100 with a 20 MOA (and sometimes 15 MOA) bases.Scharfschütze said:I have the same scope on my 10fp-le2. It has 51" of adjustment @ 100 yds. I have a 0 moa base. First group with scope at factory 0 settings was 12" low. A 15 moa base would have put me 3" high. Both are within the adjustment range of the scope, with plenty of elevation left for that 1000 yd shot.
The 15 moa base might be more preferable because you will stay closer to the scope factory zero.