shooting

[fieldsportsman 107]

hi, well now that ferreting is nearly over, im going to get my bsa supersport out in .22 with a bsa deerhunter scope, so heres a few questions

when out in the field, when i get my gun zeroed at 30 yards, what happens when the rabbits are closer then 30 or a bit further, do i aim just below or above, thanks,

[Teer 0]

Hi mate,

Generally you aim a bit lower as the impact will be a bit higher. The scope has two zeroes, one (the main zero or whatever you call it) will be at 30 yards, the other lets say at 10 yards (not sure though just guessing, but if I remember right when you zero your scope at 30 yards in .22 cal air rifles the other zero will be approx. at 10 yards.), so all the shots in between zeroes will be hitting a bit higher in general.

 

I hope it helps, cheers,

.Tomek

[fieldsportsman 107]

Hi mate,

Generally you aim a bit lower as the impact will be a bit higher. The scope has two zeroes, one (the main zero or whatever you call it) will be at 30 yards, the other lets say at 10 yards (not sure though just guessing, but if I remember right when you zero your scope at 30 yards in .22 cal air rifles the other zero will be approx. at 10 yards.), so all the shots in between zeroes will be hitting a bit higher in general.

 

I hope it helps, cheers,

.Tomek

so after zeroing for 30 do u have to re zero at 10

[zini 1,939]

Hi mate look at this diagram i have made.

 

It explains when you aim low and when you aim high.

 

This is only an example of my .22 rifle and you will need to do your own calibration when you get your rifle.

 

Si

[secretagentmole 1,701]

Note for those equipped with .177 the approximate 2 zeroes are at 14 and 35 yards (from what I have read elsewhere I hasten to add).

[fieldsportsman 107]

Hi mate look at this diagram i have made.

 

It explains when you aim low and when you aim high.

 

This is only an example of my .22 rifle and you will need to do your own calibration when you get your rifle.

 

Si

how do u read it, whats the 10 met zero

[secretagentmole 1,701]

The 10 metre zero is when the pellet strikes at the centre of the cross hairs as it flies away from the gun, it goes to a peak and then drops, striking zero again at 30 metres, the pellet does not fly in a straight line but an arc! Look at the diagram posted, it explains it well!

 

Edited because I was swapping between metric and imperial like a nervous street trader in front of trading standards...

Edited March 3, 2011 by secretagentmole

[Teer 0]

Hey mate,

 

It's quite simple. You set the scope to your primary zero, which is 30 yards. Then the scope will have another zero of let's say 10 yards. You do not zero it at 10 yards after you set zero at 30 yards. Your point of impact and aim will be the same at 10 and 30 yards. This is because when you shoot your pellet flies slightly upwards so it crosses the scopes line of sight twice (because it's got a parabolic trajectory). Look at Zini's diagram it's good. Try and understand it, and if you don't get it then come back

 

atb,

.Tomek

[zini 1,939]

Just a couple of other points lads.

 

1. A pellet does not rise up as the diagram makes it look like it does. Gravity pulls the pellet downwards as soon as it exits the barrel.

 

2. The scopes line of sight looks downwards which is why the pellet crosses it 2 times.

 

3. It doesn’t matter what rifle or what calibre you use the pellet will always impact low before your first zero point due to this is where the scopes line of sight is at its highest point.

 

4. It will always impact high after your first zero point slightly unless you zero at a range that the pellets trajectory only just touches the scopes line of sight, i.e. 18 metres for a .22 calibre rifle.

 

5. You will always have to aim high after your first zero point.

 

Si

[zini 1,939]

This is a more accurate diagram that i have just changed from a older one i did.

 

Si

Edited March 4, 2011 by zini

[fieldsportsman 107]

This is a more accurate diagram that i have just changed from a older one i did.

 

Si

so do u have to hold scope just above at 25 metres

[matt_hooks 188]

This is a more accurate diagram that i have just changed from a older one i did.

 

Si

so do u have to hold scope just above at 25 metres

 

Si uses a 25m primary zero, so he wouldn't have to. If you use a 30 yard zero, then you will need to aim LOW (hold under) at any range between the primary zero and secondary zero.

 

Think about throwing a ball. You throw it away from you, and slightly upwards. It doesn't go in a straight line, it flies in a curve. Now imagine you're standing next to a wall when you throw it, the wall represents the straight line of sight through the scope. Someone standing on the other side of the wall will see the ball appear above the wall at what we'd call the first zero, and then dissappearing behind it again at the second zero. To try and hit a target on the line of the wall in between the two you'd need to throw the ball less high. To hit a target before, or after, the "zero" points, you would need to start the ball off at a higher angle.

 

Hope that makes sense.

[pianoman 3,584]

OK.

 

Look at the diagram. (and ignore the pile of Russian shite Dragunov WTF! Si you could have used an L96!..whatever!)

 

You can see that the pellet rises and falls in an arc or curve. Like Matt says with throwing a ball. All thrown projectiles, however propelled need to fly in a curved arc to have any degree of distance. The steeper the curve is increased the greater the range distance achieved (until you reach the point of reverse-trajectory oscillation and the range of impact decreases back towrds you again, the steeper to vertical angle the barrel is presented!) Without any form of sighting, that curve would be consistently the same shot to shot, if the barrel was kept at a constant upward bearing angle.. The shot itself will not rise in flight from the barrel, we have to "loft" it a little. Now, with a scope added, your line of eyesight is travelling in a straight line through it and on to the target bullseye with the reticle, or crosshairs placed on the centre of the target.

 

You need a datum point as a given range distance to bring your line of eyesight and the pellet or bullet curved flight to meet at the exact same spot. This curve is now called trajectory. For an air rifle we will use 25 yards or metres as our primary set distance we are going to establish a centre-to-centre zero point of aim.

 

When you reduce the figure of difference between trajectory curve and straight-line of eye at the centre of the target to hit at the precise, sam spot to nothing..or zero...you have a zeroed scope/rifle with precision accurate shot-impact to the crosshairs measured at 25 yards. If you shoot at a target 12.5 yards closer than this, the shot will miss as it will have risen the full extent of the trajectory above it to fall precisely as previously set to 25 yards. Conversely, any target further beyond 25 yards and the shot will fall short.

 

Now. To hit a target further than 25 yards means raising the rifle and its barrel slightly to add a little more trajectory curve, to "lob" or throw the shot the extra distance. In your scope yoo will see this as raising the crosshairs to extend above the new target your eye is viewing through the lenses. This is called "Holdover" . Because you are effectively holding the rifle and scope over the target in order for you shot to rise over and fall precisely onto your new target. To shoot and hit the shorter range target requires you to lower your sights and effectively bring down the top of the trajectory curve to aligne onto the target.This is "Hold-under"

 

The surest way I know how to accurately use holdover and hold under, is to get out and practice shooting from a set zero of 25 yards and then, see where your shot is hitting at greater and closer ranges over a series of targets thay will record your shots impacts. This is how you build a "Trajectory map" of you chosen rifle and pellet's performance. Once you can accurately predict range estimates and can instinctively remember where on your scope reticle your shot is going to hit at the distances yopu are shooting at, you will achieve precision marksmanship of a very high standard. It just needs a lot of work and practice!

 

And as we all know, "Practice Makes Perfect"!!

 

Simon

Edited March 4, 2011 by pianoman

[zini 1,939]

Changed it especially for you Simon

 

Bring back some happy times does it pal???

 

ATB

 

Si

[pianoman 3,584]

Awww thanks buddy! Yeah I loved this rifle to bits. Accurate as a bloody lazer beam! Some great memories with some really top lads woven into this rifle Si.

 

Cheers Buddy