Scope Zero...Please Help...

I'd say it depends on your rifle, pellet weight, FPS, etc.. You need to tell that stuff.

If I set up my .22 with 14.3 gn pellets that are shooting around 660 FPS to be zeroed at 15 yards, because of the pellets trajectory, I'd have 2 zeros, the one at 15 yards and another at 27 yards. In between those two yardages, I have to hold low by varying amounts depending on yardage.

You should look up the phone app Strelok and use it to help determine holds for different distances for a given zero range and pellet characteristics.

Theoretically the further away you go the higher you need to aim probably not much for the first 25 yards but it become inversely proportional the further you go until your out of the guns range. 

I would suggest moving your target out to the distances questioned with the gun zeroed at 15 yards and shoot at the same POA (Point of Aim) as what you used at 15 yards. (don't adjust your elevation turret at this point)
If you hit above the same POA then you will use hold over at that distance. If you hit below your POA then you need to hold under.
This will also help you determine how much you need to hold over/under when shooting at those distances. 

Check out Chairgun software it's a free download and has loads of cool info that will help you out I'm sure as it has many of us.

Chairgun by Hawke Optics is another good free tool. Your FPS, pellet weight and scope height are a few of the factors in determining point of impact. Here is an example 
for a gun shooting 790FPS and using 7.9 Crosman CPL pellets. This setup is zeroed at 18 yards and scope height is 2.7 inches. At 30 yards it would shoot about 5/8 inch high then at about 43 yards it would be back on target.

Great advise from al, one important thing is your scope height. Bullpups will put your scope higher off the bore. This makes close range shooting involve more calculations, and more foregiving at longer ranges. A disco with med mounts and a bugbuster the scope sits 1.5" over the bore this gives you a pretty flat shooting gun from 10 yds to almost 40. Learn Chairgun, and don't get frustrated if your reticle is not listed. Try using generic and take note of the holdovers in inches

Theory is good...but application is king.

Set up your paper target at distances from 10 yards to 40 yards, in 5 yard increments.

Label each of the seven targets with the distance it was shot at. Shoot at the exact same spot on each target. You should see the pellet hit low in close, raise up to a peak and then start to drop off as distance increases. Look though the scope to see how much over or under the cross hair your impacrtii from each distance. That is your correction factor for each distance. Theory is good.... But hard empirical information is even better.

example with completely made up data

Yards/offset from cross hairs
10 / .75 dot low... Hold cross hair .75 dot high
15 /. Dead on... Hold on center
20 / dead on ... Hold on center
25 / 1/2 dot low...hold cross .5 dot high
30 / 1 full dot low...hold cross 1 dot over
etc. 
35
40 yards

In my purely fictional example above, the max height above cross hairs would be between 15 and 20 yards. The scope (line of sight) and the barrel are not parallel in actuality. The barrel tilts upward slightly to the line of sight. The pellet launches in an arc upwards toward the line of sight and then falls to the effect of gravity. Where the line of sight meets the trajectory of the pellet is what I call the "zero".

On my .177 setup I have point blank zero where any distance from 15-35 yards the pellet will hit within 1/4 inch high/low of cross hairs. Within that yardage I hold dead on.


I am in no way an expert and have most likely used terms incorrectly. Let's remember to have fun.