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Assistance with calibration accuracy


zini

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Hi lads,

 

I want to pass on my little calibration card to you that I made 2 days ago to help me calibrate my rifles mildots.

 

This card also assists you in calibrating your pellets ballistic coefficient (BC) at the same time via using the cm ladder system.

 

Remember that some pellets are sold with a stated BC on the tin. This figure is accurate and can be used in calibration work to a quite accurate degree, but if you want a perfect calibration you will need to test the pellets BC yourself, as all pellets are slightly different due to manufacture tolerances and act different in different barrels.

 

Some pellets are not sold with a stated BC so you need to test them anyway.

 

Remember the higher your BC the better the pellets withstand drag making them better in flight and retain their energy better.

 

Using ChairGun Pro is a very good way of calibrating your rifle to a certain degree of accuracy, but its not spot on. (sh-t in and sh-t out as they say) plus when the table says that you need to apply .21 of hold over its to fine a mark to place on a target and its better to see this amount in your mind through the scope and document it on a piece of paper or the trajectory chart also attached to this thread.

 

The mathematical algorithms work better than you would expect though and when accurate data is inputted its very, very close to the real answer.

 

There are other factors involved in calibration that we only really take into account when self calibrating, air density, precise scope to bore height, precise pellet BC, precise pellet weight and zero range to what ChairGun Pro thinks your zeroed at and what you really are zeroed at.

 

I.E, you tell ChairGun you are zeroed at 30 metres but in real life its 29.3 metres or 30.5 metres etc. All are slight inaccuracies.

 

The best way to get this correct unless you are a surveyor is to use either a tape measure or a laser, or both to be really accurate as most lasers only will show to the nearest metre.

 

People who pace out 30 yards and zero their rifle then use ChairGun will always 99.9% of the time have a slight difference in correct data to what ChairGun says.

 

Anyway use this along with ChairGun (Calculate BC from POI change) routine once you have been accurate with zero and made notes of your mildots hold overs and unders etc and it will assist you in working out you own pellets BC for future software input and better ChairGun output data.

 

I have attached a example of both cards as well for easy refenece and ease of use so please scroll down.

 

Si

Mildot trajectory chart for the forum.doc

Edited by zini
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hi si

 

i just edited and printed it and going to use it today

 

i cant believe a man like you is not famous through hunting buddy a very talented man indeed(well apart from you don't own a air arms) :tongue2:

 

thanks si great help

 

5***** and a slut point for top info

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Cheers lads for the comments :thumbs:

 

If the charts help one person then im happy :yes:

 

They work for me so will come in handy to others too i suspect.

 

Is there nothing you don't know about ballistics!?.

 

Hi Darren,

 

Yes there is tonnes I don't know as ballistics is a massive subject to learn, but I did spend 1 year learning it with my work so do understand it better than your average shooter.

 

I cant believe a man like you is not famous through hunting buddy, a very talented man indeed (well apart from you dont own a air arms) :laugh:

 

LOL Steve, its a good job i own 2 BSAs then :o:laugh:

 

ATB

 

Si

Edited by zini
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Cheers lads for the comments :thumbs:

 

If the charts help one person then im happy :yes:

 

They work for me so will come in handy to others too i suspect.

 

Is there nothing you don't know about ballistics!?.

 

Hi Darren,

 

Yes there is tonnes I don't know as ballistics is a massive subject to learn, but I did spend 1 year learning it with my work so do understand it better than your average shooter.

 

I cant believe a man like you is not famous through hunting buddy, a very talented man indeed (well apart from you dont own a air arms) :laugh:

 

LOL Steve, its a good job i own 2 BSAs then :o:laugh:

 

ATB

 

Si

 

 

lol si,im going to do a vid with ste(rossi_j) im going to be shooting cigarette filters at 50 yards(WELL TRYING)

 

atb steve

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hi si

 

will do buddy

 

i will be doing some short shots first 10,15,20,25,30,35,yards shots then after i have done these shots nic and sweet i will attemped the 50 yards shot and will video it for the proof and also show out the markings of the 50 yards,

 

atb steve

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Good bit of info there, Si, nicely done :thumbs:

 

I've been useing CGP for a while and I'm really pleased with it, the only problem I've got is I can't find the BC for the .20 Dynamics I use. Any ideas 'cos it's not on their web site...

 

Cheers.

 

Edit.... Enjoy your steak!!! :laugh:

Edited by andyfr1968
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