Posted By: Mike in A-town

## Scope question - 09/20/20 01:08 AM

I mounted a 4-32x50 on my 308. Scope is second focal plane.

It's zeroed at 100 yards and my latest target is set at 700 yards... Ballistic math says 5.5 mils of drop at 700 yards. If I leave the magnification at the lowest setting I can hit the target with a decent amount of regularity. But if I bump up to full magnification then I am completely off the map.

Is there a formula to determine my elevation adjustment when using higher magnification?

I ran a little test to see if my assumptions were somewhat correct:

1 mil at 100 yds is 3.6" So I divided 100 by 20 and of course got 5 yds. 3.6" divided by 20 is .18"

So I set up a target at 5 yards with two lines .18" apart and checked it with the scope at 4 power. It measured 1 mil. Then when I increased the magnification to 32 it measured 8 mils... That made sense. So I assumed at full magnification that 1 mil equals 8 mils, right?

So if that math was correct then I would need to divide my 5.5 mils by 8 and get .675 mils... So I held as close as I could (between .5 to 1 mil) and was still off the map.

Was I completely wrong with the math?

My 300 Win Mag has a FFP scope on it and doesn't change when magnification is increased... Much easier to use but a little more expensive.

Any help or advice would be greatly appreciated.

Mike

It's zeroed at 100 yards and my latest target is set at 700 yards... Ballistic math says 5.5 mils of drop at 700 yards. If I leave the magnification at the lowest setting I can hit the target with a decent amount of regularity. But if I bump up to full magnification then I am completely off the map.

Is there a formula to determine my elevation adjustment when using higher magnification?

I ran a little test to see if my assumptions were somewhat correct:

1 mil at 100 yds is 3.6" So I divided 100 by 20 and of course got 5 yds. 3.6" divided by 20 is .18"

So I set up a target at 5 yards with two lines .18" apart and checked it with the scope at 4 power. It measured 1 mil. Then when I increased the magnification to 32 it measured 8 mils... That made sense. So I assumed at full magnification that 1 mil equals 8 mils, right?

So if that math was correct then I would need to divide my 5.5 mils by 8 and get .675 mils... So I held as close as I could (between .5 to 1 mil) and was still off the map.

Was I completely wrong with the math?

My 300 Win Mag has a FFP scope on it and doesn't change when magnification is increased... Much easier to use but a little more expensive.

Any help or advice would be greatly appreciated.

Mike