So I'm trying to discuss this with a co-worker and I need someone more knowledgeable to let me know if I'm right or not.

If your shortest pin is set at say 20yds and you are shooting at a deer (from the ground) at 8 yds, then if you hold your 20yd pin centered behind the shoulders, the arrow will hit low.

Is this correct, I've never shot that close so I am only speculating here.  Does it follow the same principle of a rifle where the scope/sight is above the bore/arrow, therefore hitting lower at closer ranges?

Thanks.

I aim my 20pin about a few inches low to bulls eye at 10-15yds

Do you suppose that since a a bow sight sits higher above an arrow than does a scope above a barrel that the downward angle is greater, therefore the arrow intersects the line of sight sooner and the arrow hits high?

if a pin is sighted at 20 yards and you take 10 yard shot, the arrow will hit above the pin.

Bullet or arrow is acted upon by gravity the instant it leaves the barrel or rest.

At that instant it starts dropping relative to the barrel or rest.

To zero at 20 yards, the bullet or arrow must be pointed slightly up so that it arks to the zero point.

When you shoot inside that zero point, the projectile is still climbing in the arc and will hit high on the target if that aim point for a further out target is used.

This is always true except in the case where you zero something in close and the arc will intersect the aim point at 2 places as in the case of an AR-15 zeroed at 50 meters.

The bullet will hit at 50 meters, then an 100 meters it will hit 2 inches high and then at 200 meters it will hit point of aim again. This has to do with the fact that the drop  in the bullet is less than the distance between bore and how far above the bore the sights are.

But an arrow is very slow and will drop fast over distance.

With my pin zeroed at 20 yards, I must aim 2 inches low to hit where I want at 10 yards, otherwise, the arrow will hit the target 2 inches high using the 20 yard pin.


ETA: at a very very close range ( and this is dependent on velocity of projectile and the hight above bore sight that the sights are ) the arrow will hit low relative to the pin, but it would be only a few feet in front of the bow.

This is what I was basing my idea on.

Thanks for the good explanation!  Would it be the same to say that instead of the arrow or bullet point up that the sight line is pointed down?  As far as I know, the barrel of a gun and an arrow should be parallel to the ground. . .

You're onto the right idea.  If you're really close, say within 10 feet, then you're going to hit low.  For a typical distance between sight and arrow rest, the arrow leaves the bow low, cross zero around 6 or 7 yards, then goes high and drops back down to zero at 20 yards.

The 30 yard pin will cross zero even closer.  Around 4 or 5 yards.  

40 yard pin even closer, etc.

Ok, this sounds moar right.

think what  mach tis saying tis old school terms of shooting threw a pipe, rifle ya can get bye with 2 1/2" pipe,  with archery ya need a bigger pipe....

Another rule of thumb I learned was for a point blank shot, to use your 50 yd pin.

No, the sight line is not pointed down.  The sight line is straight and parallel to the ground.  When you sight in either a scope or a bow, you are actually sighting in so that your arrow/barrel are pointed up slightly to counteract gravity.

 

Aim low