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Your Zero and when you change it?

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  • Your Zero and when you change it?

    Ok so we went to the range the other day and changed up my zero for 80 degrees and 2680 fps. Question for you guys... Do you maintain one zero year round? When you re zero? i.e. say twice a year once for fall/winter and one for spring/summer? This is what I normally do but I wonder what the rest of you do.

    "1000 yards...Where the rubber meets the road!" John Howe

    "The only thing necessary for the triumph of evil, is for good men to do nothing." Edmond Burke

  • #2
    sort when I had a working rifle. I would shoot a CCB and record the deviation. also I would rezero my knobs when ever the zero was off more than 1 Moa


    • #3
      Thats a good rule of thumb I think... All of the recent silly questions by me is due to the fact that were getting into these 600-1000 yard comps. So it is naturally getting more technical, and I have all these silly questions runnin about my head. roflmao
      "1000 yards...Where the rubber meets the road!" John Howe

      "The only thing necessary for the triumph of evil, is for good men to do nothing." Edmond Burke


      • #4
        If you change locations, IE get deployed to another city, state, or country, then try to confirm your zero and change as necessary.
        Knowledge comes from retaining what is learned,


        • #5
          As said above I check my zero at the range, or where every I may be, as soon as I start shooting and rezero if needed. This is another good reason to keep a log book so you can check back and see old temp. and alt. adjustments.

          This way no matter what time of year or where I am I know I am always zeroed.

          We wasted 2hrs at a clinic on Sat. because of guys that don't keep their rifles zeroed and a couple who must have mounted their scopes the night before. rolleyes
          Know your enemies; know yourself; in a hundred battles, a hundred victories.
          Sun Tzu


          • #6
            SORT, I'm not a pro, but this is what I do:

            In my country we have very cold and also very warm days in the winter so a seasonal change of the 100 m zero is not useful.
            Since 95% of the time the altitude variation is small (less than 500 feet), I just record the POI changes at all ranges depending on temperature and shoot accordingly. The temperature affects muzzle velocity and air density, the effects are very noticeable, and you have a quick "built in" temp measurement in your skin.
            Of course at long ranges (700+ yds) baro pressure correction would also be indicated, but that's fine tuning. I don't bother about humidity.

            If I moved to a place with very different environmental conditions then I would change my baseline zero, and if the seasons were marked I would probably change it too.


            • #7
              Here's my take on the subject;

              Since I keep a 100 yard zero on my SWS there is seldom any significant change to that zero no matter where I am.

              For example; Last year, I went from Camp LeJeune, NC (sea level) to The Whittington Center in New Mexico (6,600' ASL). My 100 yard zero showed no measurable change. However my long range data was WAY different. 1,000 yard data went from +36 moa to +31 moa.

              Rezeroing your SWS is good but it won't compensate for the real changes that will be found further down range.


              • #8
                I re-zero for Dead On at 100 yards any time I see that my Zero has shifted any up or down that is enough for an adjustment. This is subject to change depending on shooting conditions also. I Reset the M1 Elevation Knob back to "0" and Note the adjustment in my log book. When you qualify monthly this will keep your confidence level very high that your equipment will perform 100% on demand.
                Viper 225 Out


                • #9
                  This is a good topic! I found a change on my 100 yard zero at a match today. With my 100 yard set on my M1(0) I found that my first shot was high at 100 yards on a 1" dot. The next shot hit right next to the first shot. I held low on the dot and hit center. I drop 1/2 Minute and the rest of the shots feel in. I had to do the same think at 2,3, and 400 yards.
                  I also had a slight change at the SniperQuest match. When I checked my zero at the range and it change a little. Maybe a couple of clicks. This happens. There can be several thinks that can affect this, Temp,Humidity, and elevation. Just my 2 cents worth. mildot
                  "Learning to function under all types of situations and always maintaining good marksmanship skills is imperative to effective performance with the precision rifle."



                  • #10
                    Interesting topic indeed My thought on it is that I do not want to lose my know zero because that is the reason we keep dope books. By changing the zero for the season you negate the accumulated data from your book, therefore you would have to fine tune your zero each range session then reevaluate trajectory. MHO, it defeats the reason for all the record keeping of POA - POI in all the known environmental conditions that change your trajectory.

                    However when I travel a distance to a shoot such as the SPSC, ( held in Texas, I live in Ohio ) all I do upon arrival is re-zero at 100 yards, but keep track of the adjustment by writing it down. If memory serves correctly, my Texas dope is ½ MOA low and ¼ MOA right of my Ohio zero, so while in Texas I’ll set my knobs to the correct Texas zero and return them to my home zero at home. It’s just begging for a miss to try and remember the OH –TX adjustment on top of the elevation and windage correction in the heat of a competition. Then when I get home, everything is right where it should be and where all my dope is known to me.

                    So if you travel, re-zero, but keep track and write down the changes. I find that my known dope is very applicable to the new location with the new zero.

                    This advice and sixteen quarters will get you a frothy café mocha with a curly straw.

                    "Why, they couldn't hit an elephant at this dist...."
                    Last words of Maj. General John Sedgwick
                    09 May, 1864 - Spotsylvania


                    • #11
                      Why do snipers have such a short range zero? I thought that snipers rarely shoot at distances less than 300 yards. Why is 100 yards the standard zero?


                      • #12
                        Snipers zero at 100 yards for several reasons.

                        First of all it is convenient. The norm at most American rifle ranges is to have a 100 yard line with target backers. At 100 yards the hits can easily be seen through even a 10X scope and adjustments can then be made without the aid of a pit crew or a high magnification spotting scope.

                        Second, not all snipers have an offensive military mission. For law enforcement snipers a 100 yard zero puts their zero very near their most likely engagement distance.

                        Finally, modern sniper scopes with elevation adjustment dials the 100 yard zero simply affords a zero point for range/elevation adjustment and the distance of that zero point is really irrelevant when you are capable of dialing in elevation corrections for range.
                        During Viet Nam the USMC issued a Redfield 3X-9X hunting scope that didn’t have “target knobs”. So the solution for them was to zero the rifle at 500 yards and then apply hold-over and hold-under referencing anatomical aiming points.

                        There is one “sniper scope” that requires a 200 yard zero and that is the Springfield Armory model with the ranging/hold-over reticle. My best advice here would be to avoid that particular piece of hardware.


                        • #13
                          Record your cold barrel zero. See if there are slight changes from that as you fire. Your first shot out of a clean rifle can be a little off compared to shots after you have fired it several times. Pay attention to the wind and other envirmental changes even at 100 yards. It could move you point of impact .5 MOA or so depending upon conditions. IMHO.