Scope Levels- Why?

[blvette75]

Forget the cosine indicator; get a SIG Kilo 2400 ABS. You don't have time to do all the math when hunting, and even if you do you can make mistakes. The Sig Kilo 2400 ABS corrects for inclination/declination. Will see how well it compensates for altitude on my Colorado property this weekend, which is about 8000 feet.

Thanks, I was looking at one of those as my current range finder only goes to a 1000 yards.

 

[Pro2A]

It would be awesome if a manufacturer could incorporate a level in to the scope, similar to how they're incorporated on many archery sights.
Maybe this exists and I just haven't seen it?

Sig Tango 6 has their LevelPlex electronic level built into the scope with visual indicator visible in the scope. Don't know of other manufacturers doing this.

 

[Pro2A]

The error has to increase with distance, so just like spin drift, it is .01 MOA at 100 yards with my load. at 1000 yards it becomes 1.0 MOA . Any alignment error gets greater, the farther distance it travels.

If you draw a straight line and make it 1o off, it will stay 1o off for ever but the distance from the targeted point with no 1o offset will get greater the farther the distance gets.

To a smith like myself and many more, any error is a problem so we avoid any thing that is not true and level. Nothing is perfect, but we try to get as close to it as possible so top performance is possible.

No one is really wrong to the point that they cant compensate for errors, But it is just easier to make something easier so you can concentrate on other variable things than need to be compensated for like wind. If everything is true and level, wind value is normally one adjustment. If canting the rifle, you have to add the wind effect and the canting effect that can be both more wind and elevation in addition to wind value.

J E CUSTOM

JE CUSTOM, as you point out, vertical displacement for an angle (MOA or MIL) grows linearly with distance as it is line of sight. However, the cant error is not linear with distance as it relates to ballistic trajectory. . Cant error magnifies as one dials more for greater distance as the come ups increase because cant results in only coming up vertically a percentage of the amount dialed with a growing amount of horizontal displacement. Cant yields a reduction in actual vertical displacement dialed and a growing horizontal displacement. A flatter shooting bullet doesn't get impacted as much by cant because less come ups are dialed....yielding less error. Similar to the impact of inaccurate turret adjustments tested by the tall target test, and resulting scaling required to get accurate come ups. In Shooter's MOA (1.0" @ 100yds) 1MOA at 100yds = 1"; 2" @ 200yds...10" @ 1000yds. However, cant error grows with distance (not linear) in proportion to the come ups of the specific caliber/bullet combination. The more come ups required the more the cant error...ie. between two calibers. There is more horizontal error than vertical error from 0deg (true vertical) cant until 45deg. At 45deg the horizontal and vertical error are equal. Beyond 45deg to 90deg the relationship reverses with vertical error being greater than horizontal error. Cant is represented by the clock hand as it moves off of vertical at 12 0'clock. This is easy to visualize with a clock hand tip moving off of 12 o'clock toward 3 o'clock. Look at the horizontal and vertical displacement segments of hand tip movement. Actual dialing movement is along the clock hand. Totally vertical at zero cant (12 o'clock). Declining vertical movement and growing horizontal displacement as the clock hand moves away from 12 0'clock toward 3 0'clock.