Sighting in a scope……….Using Trajectory

[Oneshotwillie]

https://www.pyramydair.com/blog/2011/02/episode-20-how-to-use-trajectory-to-sight-in-a-scope/

The above vedio suggest using 20 yards to sight in your scope and it will be good from 0 out to about 34 yards?  Is 20 the magical number to be able to pick up your springer and hit something between 0 and say 35 yards without the use of mil dots?

I have about a 35 yard shooting distance in my back yard.  I also have Purple Martin houses with in that range.  I would like to be able to pick up my gun and shot sparrows off my Purple Martin houses from any distance with in a 35 yard range!  So I guess my question is how is the best way to sight in a scope to accomplish this?  Do I need a scope with dots or if it is set at 20 yards will just a scope without dots work?

[Back_Roads]

 It will vary slightly from gun to gun, more like a rough estimate to get you in the ball park, best to test it on targets set out at 5 yard intervals. and it is more like it will be in the kill zone from 15 - 35 yards, @ 10 yards there is some holdover involved.
 
I use the 2 zero method on most of my guns, some are set different depending on power and the  purpose of the gun.
 
A standard duplex scope is ample, also the degree of incline if shooting upwards will change the POI, if all you do is shoot at that angle and range you could sight in your zero at that range and leave it there, just remember you wont hit anything you aim at at other distances or angles most of the time.

[Bullit]

X2   The 20 yard primary zero point is a starting point.  Set your first target at 20yds and get sighted in.  Then you go to your second target at (say 35yds).  Shoot at the bull.  If your pattern is above the bull, then your "Secondary Zero" point is farther than the 35yd mark.  The pellet still has some elevation and "gas left in the tank".  If the pattern is lower than the bull, then your "Secondary Zero" point is closer than the 35yd mark, as your pellet is falling and running out of gas, so to speak.   By moving that target back or closer, you can find this exact yardage of your Secondary Zero.  You know your Primary Zero already...so you'll have both.  Setting various targets at yardages in between these 2 points, you can observe and note where the pellet hits at these distances to get an idea of your holdover required...if any.
You can site in just a couple yds closer, and find your Secondary Zero may increase because
you increased the launch angle. I have a 12fpe .177 sited in at 18yds, and it's very close to dead on, from a range of 15yds out to 40yds.  You'll find your rifles' optimum primary zero in time.
Chairgun is a free download that is very accurate, and is a timesaver.  You can get close and not have to spend so much time setting and adjusting different targets. Shows pellet trajectories and data on the pellet during flight.  Accurate input gives best results.  Well worth playing with and learning what all it can do.  Give it some time:
http://www.hawkeoptics.com/chairgun.html#.Ud7Ah6xBFiw

PS:  I am a big fan of the Mildot reticle.  The dots help you with holdover and holdunders. The glass etched 1/2 Mildots are even more precise, with smaller dots, and smaller spaces between them.  Hope this helps.

[Airgun.Sniper]

 What your looking for is optimal zero? Ive done this on a card board box. shot at 10 20 30 40 50 yards with a zero of 20 yards....then i shot at 10 20 30 40 yards with a zero of 35 yards. I then trace the trajectory and find out whats the optimal zero for my particular gun and scope


Cheers

 jay

[anuthabubba]

I like the Optimum Point Blank Zero. You can expect to hit your chosen bull size/kill zone over a wide range from a single sight picture, which can be adjusted for range in the field, with experience in its use.

http://www.arld1.com/trajectorypbr2.html

Not really useful for shooting groups, at a fixed/known distance, on paper.