Zero Range For Decline Incline Shooting

[ghillies 209]

you might bre able to guestimate the power and fps using chairgun and the drop at diferent distances (on the horizontal), same with the BC.

[PaulEamonn 37]

Hi Craig

I can't see the logic of zero a rifle at any other distance than 25 yds (for trajectory). There is, however, a lot of logic in zeroing a rifle at further for lateral accuracy (windage).

The reason I say this is because, according to Chairgun Pro, 25yds is the point at which pellets fired from virtually all air rifles hit but don't break the line of sight. This means that the adjustments you need to make when aiming at a target further than 25 yrds will always require hold-over. Never hold-under. However, if you zero at 35 yds, for example, your pellet will pass through the line of sight at about 14yds and 35yds. In between these two points the pellet will be above the line of sight therefore requiring you to give it some hold-under.

In my opinion, remembering hold-over is difficult enough and so the last thing I want is to have to remember hold-under too!

As for lateral zeroing, using a distance further than 25yds is fine because, the further the target, the more discrepancy there will if you are off zero. So, once you zero onto the vertical line, your zero should be more refined than if done at a shorter distance.

Having said that, you need to do this long distance lateral zeroing when there isn't any wind or else it will be pointless.

Regarding 'inclined' shooting. I've recently taken up roost shooting after having read about it being a good way of getting pigeons. So I rigged up a target at about 30yds and at about a 25 degree up angle. I was surprised to find that. when I aimed at the centre of the target, my pellets still hit pretty much centre. This I put down to the distance being further than my zero range of 25yds (which would normally result in my pellets hitting a bit low). But this was then counteracted by the fact that you need to aim low when shooting at an incline.

When I took to Chairgun Pro, I was surpised to find that this need to hold-under isn't all that severe after all. I've attached a couple of pictures of Chairgun Pro showing this.

Personally, having said all of this and spent a lot of time on Chairgun Pro in search of the perfect combination, I would still suggest that you do the following.

1. Zero at 25yds (on the level) on a calm day.

2. Put some targets out to your maximum range every 5yds and fire a few shots at each of them. By doing this you'll learn confirm what the actual holdover needs to be for each distance. Don't forget to use the magnification that you'll use while hunting and then keep to it. If you change the mag, it will change the mildot pattern for holdover.

3. Then do as suggested by Reaper and go to your permission and set the targets out at the same ranges and shoot a few more into them. Once you've done this just read off the mildots and make notes of them. You'll find that the readings will be different for the area that's at 30 degrees to the one that's at 45 degrees and these will be different from the readings on the level.

By doing it like this, you won't need a chrono or any workings out on Chairgun Pro to know where to aim whether you're shooting up, down or sideways!

There is no substitute of actual shooting practice in all the different situations you're likely to come across irrespective of how good your simulation software is!

[Craig Fosse 286]

Mate that has made things a lot simpler, I'll change my zero from about 30 ish yards down to 25, much appreciated mate thanks a lot! Hopefully this means no change of hold under when shooting downhill

[Craig Fosse 286]

So basically am I right in saying on the flat decoying pigeons if I get any birds between 0 and 30 yards there won't need and hold under?

[PaulEamonn 37]

Hi Craig

 

If you zero at 25 yds you shouldn't need to hold-under for any shots and, if you're shooting at a target with a 1" kill zone, you should be able to aim on the cross of the reticle when the target is between 15 and 30yds and the POI will (should?) be between the line of sight (where you were aiming with the cross of the reticle) and about 1/4" below the line of sight.

 

On the flat, the only time you'll need to use 'hold-over' (where you're holding the cross of the reticle above the Point of (Intended) Impact) is when you are shooting at something closer than 15yds or further than 30yds.

 

Below is the theoretical retical (try saying that five times when you're pizzed)! for a x8 mag zeroed at 25yds. As you can see from the numbers on the left, to shoot at a target at 13yds the hold-over is 1/2 mildot. For 10yds it's 1 mildot. On the right handside of the line it's 1/2 mildot for 38yds and a whole mildot for 46yds.

 

Obviously, if you're shooting on an incline, these figures will change and be like the ones shown in the reticle image I attached to my previous post. In this case, you will be using hold-under (where the cross on the reticle is below the intended POI). But, in reality, the best way is to go out to your permission and set out the targets at different ranges. You may be surprised at what you'll learn.

[Craig Fosse 286]

Cheers mate much appreciated, if I'm shooting on a decline between 15 and 30 yards I. Reality I shouldn't need much hold under if any correct?

[PaulEamonn 37]

H Craig

 

Yes that's about right for the part of your permission that has a 30 degree slope. You could even extend that out to 35yds.

 

But the area that's got the 45 degree slope, you'll need to give it a bit on distances past about 20yds. About half a mildot should do it out to 35yds.

[Craig Fosse 286]

Cheers buddy thanks