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Question optimum zero range

Discussion in 'Anything Airgun Related' started by Snipertez, Jun 8, 2014.

  1. Snipertez

    Snipertez Donator

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    Just been wondering how others like to set up there scopes ?

    Since getting the time to have a play with Hawkes Chairgun pro software, l'm now questioning my primary zero setting of 40m (with 177 @ sub-12fpe)

    After trying a few different profiles and then finding the optimum switch, the Chairgun program took me each time to a trajectory setting with no hold-under and a longer point blank range (pbr) with only hold over points besides.

    My initial reasoning for using a 40m primary and some hold under in-between, was to keep the other range settings closer to and around the central crosshair. But after a good digi-play, re-setting to 27m seems well worth a try. Surprisingly !?!?

    27m = PBR from 11m out to 32m (12mm kill zone) and then only hold-over for the other distances. I say 27m as this then also gives good set ranges on the MTC SCB ret' mil-dots.

    As l say, l'm interested to hear others thoughts on this.
     
    Last edited: Jun 8, 2014
  2. larryking28

    larryking28 Busy Member

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    I tend to zero at 30 yards.
    With .177 I am then pretty flat from 25-40 yards.
     
  3. terry1001

    terry1001 Major Poster

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    It will depend to some extent on your scope reticle and the different aim points. Chairgun can answer the question for you if you have a Hawke (or mil dot scope). You will need to know your pellet (easy enough), muzzle velocity and scope height. If you input this information into Chairgun with the appropriate reticle it will also tell you the optimum zero range.
    On my .177 I set zero at 35 yards and then I adjust the scope magnification in Chairgun until the reticle marks coincide with sensible ranges, on a SR6 reticle I can set it at 12x and the reticle gives 35,40,45,50,55 and 60 yard intercepts which is fairly easy to remember. Not all reticles will work out quite as well but you can play around with the settings to see if anything suits you.
    Once you have this worked out then it's time to check the settings by shooting as, if your scope zoom ring isn't perfectly marked, you may be out by a bit and have to adjust the zoom to get it spot on.
    For a .22 I zero at 30 yards and do something similar to the above. Of course if you don't need to shoot further than, say, 30 yards a different setting would be more appropriate. At least in Chairgun you can run through all the scenarios in a very short time and without needing to fire a shot until it comes time to check it all out.
     
  4. Dag

    Dag Pro Poster

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    When I bought my first air rifle last Autumn I fell into the trap of thinking the furthest zero possible was best. As I read posts here and saw how useful Chairgun was for "whatifs" I realised there was much to be gained from cutting down the distance to the furthest zero. The biggest advantage was that setting the rifle and scope up for 30yds gave me a near zero of approx 18yds which just happened to match the distance from inside my garage to the furthest corner of the garden.
    Now, if I feel that there is something wrong with my setup, or I am changing pellets or have made other alterations, I can zero at 18yds and know from Chairgun what my furthest zero will be to within a couple of yards before I can get to the range and check it out and make final adjustments.
    Chairgun isn't foolproof but it can be fun and can get you within a few yds of your desired far zero without wasting too many pellets...or scaring off your quarry if you are into hunting!
    Dag
     
  5. Bemused

    Bemused Engaging Member

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    Optimum zero I found depends mostly on what you actually use the rifle for, ie FT, HFT, Hunting, Plinking etc.
    Also how you use your optics and what type of retina you have, ie hold over or turret clicks, MIL dot, SR Pro etc.

    It an area as a novice that I found confusing.

    35 yards primary seems to work for me, shooting FT and plinking with 177 at 8.44 grain, a Sidwinder 8-16x56 SR Pro and 11.6 ft/lbs.
    But I have a suspision it may change in the future as I gain experience.

    It would probably help the clever guys if you explained what rig you have and what you use it for.
     
  6. metalman

    metalman Big Poster

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    I zero everything(.177/.22) at 30 tds and learn holdover/under. Paper punch out to 60yds and make up a rangecard. Only hunt and plink
     
  7. Speed

    Speed Busy Member

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    i have my ft rig with a 30yard zero, so all my clicks are all turning the turret upwards, i tried at 35 buy had to go -3 clicks to get 30yard

    for the springer i also zero at 30 yard, only really shoot to 45yard with the springer and on my scope its 1 mil dot down
     
  8. yorkshireshoot

    yorkshireshoot Posting Addict

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    30 yards seems to be the norm I think it's best to just get out plinking and learn hold over/unders . Chairgun can make things a little too complex but if your into that kind of thing then maybe a 28.4728790 yard zero may be better :)
     
  9. Snipertez

    Snipertez Donator

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    Hi guys, yes, the versitility of the software is what l'm impressed with mostly and l do appreciate its only a guide. But l more appreciate the range time saved with the trajectory simulations possible. l've known of this software, but only very recently had a more serious dabble with it.

    l have a HW100 tk fsb with an MTC Mamba 3-12x44 (scb mil-dot ret') set low and she likes AAFields. l only hunt and thought l had the best set-up for my needs until l started to play with the software. lts now got me thinking about trying somethings differently. l would always set up targets every 5m out to whatever and punch it out the old fashioned way. But having had a good play on chairgun its given me a fresh perspective on this procedure that a ton of paper punching would have been needed for in the past.

    So, now looking forward to having a play on range and getting a new set-up sorted, more than likely.

    edit - oh, and by the way, l don't click, l just ret' and shoot :rolleyes:
     
    Last edited: Jun 8, 2014
  10. tintin

    tintin Engaging Member

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    I zero at 25yds. Everything is either on crosshairs or falls below on my particular setup using ultra light pellets at 845fps with a 32mm front objective sitting as close to the barrel as possible.
     
    Last edited: Jun 8, 2014
  11. Gunfun

    Gunfun Engaging Member

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    I have a normal memory & multiple guns so I use all mildot scopes to keep it simple. In .177 on my x20 half mildot scopes the holdover is -
    Zero = 27m
    1/2 mildot = 35m
    1 mildot = 40m
    1 1/2 mildot = 45m
    2 mildot = 50m
    This keeps things simple, easy to remember and accurate.
    With chairgun always check every holdover on the shooting range, The differant types of rifeling, length of barrel and barrel choke will affect the BC of the pellet compared to Chairgun, I found the longer ranges 40 to 50 meters were off by 10 to 15 mm, so I went back to chairgun and adjusted the BC until I matched my shooting range results, and then adjusted the zero until I got my required holdover distances.
     
  12. terry1001

    terry1001 Major Poster

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    Your advice is sound although the reasoning is slightly off. The BC is independant of the rifle and is based on the physical properties of the pellet. If you put the correct values for muzzle velocity and scope height into Chairgun it will give you a set of figures, if you then change the magnification slightly you will see a change in these figures. Unfortunately the magnification markings on the scope are rarely accurate so you may get the figures for 10x mag from Chairgun, ritate your zoom ring until the 10 is opposite the little dot but actually be set to 9x or maybe 10.5. Checking your values by shooting is the sensible way to confirm that you've got it right and if your long range holdover isn't qiuite spot on then a slight tweak of the zoom will put you right. It's probably simplest to get your zero sorted at your normal range and then move the target out to 50 yards and adjust the zoom until you are spot on with the calculated holdover and you should then be ok for all ranges.
    Every time you alter the zoom setting all the multi aim points will also alter, unless you have a first focal plane scope of course.
     
  13. Snipertez

    Snipertez Donator

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    Yes, thats the other thing l'm also having a play with, the zoom and how it alters the trajectory. Very interesting indeed and there are alot of potentialy different scenarios to look over to.
     
  14. Gunfun

    Gunfun Engaging Member

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    Hi Terry1001 & Snipertez, sorry I'm a bit late in my response,

    When I get a new mildot scope I always check the Mildots size at the specified magnification (I mark 30mm intervals on a piece of white plastic, approx 10 marks in total & place the plastic sheet at a measured 30 meters, then adjust the scope to match the marks & take note of the exact position of the magnification ring) i.e. if the manufacturer states "true mildot at x10, does the scope datum mark line up with the "1" or "0" of the x10 on the magnification ring. I have to do this because I use different manufactures of mildot scopes and as Terry1001 states it does vary alittle,.

    The reason I think the BC is different between different barrels because of the rifleing pattern impressed on the head of the fired pellet, for example my verminator hardly leaves any marks but my HW100 leaves a number of deep square rifleing marks around the head of the pellet, I think these marks may affect the pellets BC.

    Also if a barrel is choked I think there will be some deformation of the soft lead pellet, which will also affecting the BC.

    If a barrel is very short it will require a larger & faster pulse of air to accelerate the pellet to the same velocity as a longer barrel, I think this could also deform the pellet skirt differently between two lengths of barrels given the same velocity & therefore affect BC due to aerodynamic drag.

    Please note lads, the "I think" get out clause on the points above, I have no way of proving any of this, I read it on another thread and would welcome anyone with factual knowledge of the above to further enlighten me.
     
  15. terry1001

    terry1001 Major Poster

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    Ballisticboy may be able to offer an informed opinion on any variation in BC which might arise from the pellet being fired from a variety of rifles. It is possible to obtain values for the BC by measuring pellet drop or velocity at different ranges, Chairgun Pro does offer ways of doing this and arguably an experimental method may give a better value for use in that program. The problem lies in finding a suitable venue with no wind etc and in being able to measure precisely enough.
    The method for checking mil dots is very useful and well worth trying by anyone who uses mil dots for holdover or rangefinding. I recently checked a couple of scopes for which I had calculated (from Chairgun) magnifications which would give sensible values for the reticle marks. In both cases a slight tweak to the zoom was required to get them shooting on at 50 yards after zeroing at 30 yards. In the worst case the error was less than an inch and was quickly eliminated. The calculations are fine but need checking by shooting before you rely on them.
     
  16. Gunfun

    Gunfun Engaging Member

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    Brilliant Terry1001 ! I'd never got as far as thinking about checking the velocity at different ranges to confirm this, top one. This is what this forum is for, thanks.
     
  17. mark112

    mark112 Engaging Member

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    Hi,

    Surely the way the rifling marks the pellet and compresses it through the choke together with how the pellet is shoved up the barrel and thus skirt deformation (violent blast v gentle shove) MUST effect the BC of the pellet. They are after all effecting the shape of the pellet are they not. I calculate my own BC's in chairgun using 'drop at range' function (usually at 50 yards) and the BCs calculated are not the same figures as supplied in the pellet database provided. My calculated figures do fit may own range tests afterwards much closer though.

    Mark

    P.S. If I had read this thread to the end I would have realized all the above has been mentioned above. Oops!
     
    Last edited: Jun 24, 2014

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