Rifle scope zeroing question...

[MistWolf]

You will have two zero points

Not always. Some zeros are such that the bullet only meets the line of sight once, then drops.
View attachment 699685

Here is a good graphic to go along with the one Art posted that will help further explain that there is no bullet rise
View attachment 699686

 

[ohbythebay]

Actually...

They are both correct...Art's picture shows a parabolic arch with the gun angled upward...and clearly shows the two intersection points.

On mine, I was trying to depict the short distance straightline round with the scope sighted to 25 yards. In doing so, at 100 yards it will appear that the round hits high...because the scope focus was sighted at the 25 yard make causing a persistent downward angle.

I could reverse this with they scope sighted at 100 so at 25 yards, the rounds would appear to hit low...

 

[ohbythebay]

Okay...got it

Thanks for the pics folks and the explanation...

 

[chaser_2332]

bullets do not rise, they start to fall as soon as they exit the muzzle. You can point the muzzle up and give the illusion that it is rising.

 

[DPris]

Bullet rise is the simplest way of referring to the idea that bullets will rise above a given aiming point at certain distances for those not otherwise familiar with the mechanics of gun/bullet interaction.
Denis

 

[strambo]

An AR zero'd at 25 yds will likely be about 6-8" high at 100. 2" low is a good start.

 

[ms6852]

This is what really happens, in the military we all zeroed our M16A1 at 25 yds and were dead on at 250 and clearly effective beyond 300 yds with just a little kentucky windage hit targets at 400 yds w/o scope.
http://thearmsguide.com/wp-content/uploads/2013/09/IMG_5242.jpg

 

[DPris]

In the military, you typically got one data set through one barrel length & weight with one load (possibly two different loads, depending on what you were issued), and not a lotta variation in sighting planes.

Very limited data, and the goal was not to hit a baseball at 100 yards using a 25-yard zero.

Military has the objective, for the average infantryman, of putting a bullet in a human torso out to 300 yards or so.
The 25-yard zero CAN achieve that & if that's all you want in terms of accuracy, go for it.

Remembering again that in the non-military world, there are so many variables in what the rest of us are shooting that the 25-yard zero simply is not the end goal in longer-range zero & accuracy.

Stating how the military does it really isn't very useful.
Different parameters, limited variables, limited data.

Denis

 

[matrem]

If an AR is zeroed at 100 yards, the bullet will generally only touch the line of sight at one point, which would be of course, at 100 yards

While I agree with post #26, I'm sure not buying that.

Assuming roughly a tenth of a second to go the 300', and scope mounted even three inches above bore center;

Gravity pulls faster than that.

 

[matrem]

After thinking about it more, it may be possible if scope was way "down" in its vertical adjustment range.

Something I've not tried, but going to.