Yardage Zero

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  • KingJD79
    Unwashed
    • Dec 2015
    • 18

    Yardage Zero

    Last night I got my new Vortex PST 6-24x50 SFP. Tomorrow I pick up my Grendel from the local armory after my mandatory 10 day wait. Sunday I plan on going out and putting a zero on this rifle and had always leaned towards a 100 yard zero. The mount for my scope is the 20 MOA ADA mount.

    I've seen a few guys go out and zero their grendels at 200 yards and even some other odd yardages. My main purpose for this rifle will be your good ole headed out with the boys to pop varmint and while in season use it for deer and elk.

    Can someone tell me why I would benefit putting my zero at a range other than 100 yards? Do I plan on going out and making 1000 plus yard shots anytime soon? No, one day I will but I see the furthest shot I may take in the next 8 months will be 600 yards while I'm hunting up in Colorado this November.

    Any advice, knowledge and humor is appreciated.
  • LRRPF52
    Super Moderator
    • Sep 2014
    • 8569

    #2
    For hunting, a lot of people like a 200yd zero because you don't need to dial or hold for any shots within 250-260yds, depending on your barrel length.

    To make a 200yd shot with a 100yd zero, you need to dial or hold .4 to .6 mils.
    NRA Basic, Pistol, Rifle, Shotgun, RSO

    CCW, CQM, DM, Long Range Rifle Instructor

    6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

    www.AR15buildbox.com

    Comment

    • kmon
      Chieftain
      • Feb 2015
      • 2095

      #3
      I am one of those that prefer a 200 yard zero for hunting for the reason above and have been doing it that way since well before reliable dial scopes were available. For long range with the scopes and rifles I have for that I still use the 200 yard zero since I am accustomed to it and have DOPE charts made for the way they are setup.

      Comment

      • JASmith
        Chieftain
        • Sep 2014
        • 1620

        #4
        Many of us don't have easy access to 200 yard ranges.

        Setting the sights so that the impact is 1.5" high ad 100 yards does about as well as 200 yards. One can build dope charts around the zero as easily as can be done for 200 yard zero.
        shootersnotes.com

        "To those who have fought and almost died for it, freedom has a flavor the protected will never know."
        -- Author Unknown

        "If at first you do succeed, try not to look astonished!" -- Milton Berle

        Comment

        • 65Whelen
          Warrior
          • Sep 2014
          • 671

          #5
          Can I add a hypothetical here, using factory Hornady SSTs where would zero be to have +/- 4"?

          Comment

          • terrywick4
            Warrior
            • Sep 2014
            • 181

            #6
            Originally posted by 65Whelen View Post
            Can I add a hypothetical here, using factory Hornady SSTs where would zero be to have +/- 4"?
            with my factory amax load I have a zero of 250 yds. at 300 is it is 4" low and at 100 it is 3" high give or take some .0?

            Comment

            • Klem
              Chieftain
              • Aug 2013
              • 3508

              #7
              200yd zero is because people want an average 'Point blank range' (PBR).

              The idea of a PBR is to zero for the maximum effective killing range for a certain diameter of target. That way you don't have to worry about elevation/range, just point and shoot. Hunters, especially those without the ability to crank the elevation quickly in the field use this.

              For example, if you think a bullet hitting anywhere in a 10cm diameter circle will kill your target, with a 123SST at 2560fps then the PBR zero is 231metres. By zeroing for 231M the bullet will climb to apogee at 130M and eventually drop to 10cm low at 270M. You can point at the centre of your 10cm target and be confident of killing it out to 270M.

              For a 231M zero you can pace this out on a range but probably better to find out where the ballistic curve will be where the targets are on your range. For example, on the above ballistic curve it will be 9cm's high at 100M. Or, find out where the first time the ballistic curve crosses paths with the line-of-sight...For the above it is 30M. For a 231M PBR you can zero at 30M or 231M. Or, make your MPI 9cm at 100M.

              If you want to shoot small varmint targets it may not be in your interests to PBR zero.

              Comment

              • JASmith
                Chieftain
                • Sep 2014
                • 1620

                #8
                Originally posted by Klem View Post
                ...If you want to shoot small varmint targets it may not be in your interests to PBR zero.
                Klem, your caution perfectly describes why I went back to the advice given on many sight-in targets.

                I played with the maximum point blank range for a long time, and then realized that the practice was at odds with how I actually do informal practice. The informal practice for me and the folks I shoot with almost always involves small objects ranging from dirt clods through to various sizd frangible targets. Frangible targets include clay pigeons and various water-filled containers. The water-filled containers are easy to recover and facilitates range clean-up.

                For example, let's a zero of 1.5" (3.8 cm - rounds to 4 cm) high at 100 yards (91 metres) for the 123gr SST / AMAX with a muzzle velocity of 2500 fps (760 m/s).

                This condition keeps the bullet within 4 cm of the line of sight out to a tad beyond 175 yds 160 metres) which is close enough to assure hits on most targets of rat size and larger throughout this "point blank" range. At the same time, the point plank range for a 10" dia (4cm radius) vital zone is about 225 yards (205 metres).

                If I go to the trouble of calculating the maximum point blank range for that 10-inch circle and then sighting in for the indicated height at 100 yards, then the medium game point blank range goes out to 300 yards but with the cost of a lot more effort figuring out hold over and hold under for practice targets. An animal more than 225 yards out but within is generally relaxed enough for the hunter to remember to hold closer to the spine or back.

                Then there is the subject of when one should use modern technology to measure range and calculate holdover, etc...
                shootersnotes.com

                "To those who have fought and almost died for it, freedom has a flavor the protected will never know."
                -- Author Unknown

                "If at first you do succeed, try not to look astonished!" -- Milton Berle

                Comment

                • Klem
                  Chieftain
                  • Aug 2013
                  • 3508

                  #9
                  I don't use a PBR's. PBR's make a mockery of all the fancy kit I've spent too much money on. Laser rangefinders, exposed tactical turrets, Kestrels and ballistics programs.

                  I zero for 100M and remember the following Mils come-ups;
                  0.5 for 200
                  1.5 for 300
                  3 for 400

                  Those numbers get me on target between 0-400M, which covers all of my hunting.

                  When accurate shooting from the bench the come-up's are the real ones; 0.6, 1.6 and 2.8Mils, but the 0.5, 1.5 and 3 are easy to remember and convenient stadia intersections on the Mils reticle to aim with.

                  If I have time then I lase the target and use the ballistics program for the actual corrections.

                  All my shooting and ranging is metric so when you guys talk I have to do mental conversions.

                  Comment

                  • JASmith
                    Chieftain
                    • Sep 2014
                    • 1620

                    #10
                    Originally posted by Klem View Post
                    ...All my shooting and ranging is metric so when you guys talk I have to do mental conversions.
                    ...and, as you can see, including the conversion in-line really clutters things, but itnis a way to understand each other a bit easier.

                    I wonder if the web browser can be trained to translate ''strailian to 'merican and back including units cnversions?
                    shootersnotes.com

                    "To those who have fought and almost died for it, freedom has a flavor the protected will never know."
                    -- Author Unknown

                    "If at first you do succeed, try not to look astonished!" -- Milton Berle

                    Comment

                    • LRRPF52
                      Super Moderator
                      • Sep 2014
                      • 8569

                      #11
                      Originally posted by Klem View Post
                      I don't use a PBR's. PBR's make a mockery of all the fancy kit I've spent too much money on. Laser rangefinders, exposed tactical turrets, Kestrels and ballistics programs.

                      I zero for 100M and remember the following Mils come-ups;
                      0.5 for 200
                      1.5 for 300
                      3 for 400

                      Those numbers get me on target between 0-400M, which covers all of my hunting.

                      When accurate shooting from the bench the come-up's are the real ones; 0.6, 1.6 and 2.8Mils, but the 0.5, 1.5 and 3 are easy to remember and convenient stadia intersections on the Mils reticle to aim with.

                      If I have time then I lase the target and use the ballistics program for the actual corrections.

                      All my shooting and ranging is metric so when you guys talk I have to do mental conversions.
                      I find myself doing this as well, since I have target turrets, and pay very close attention to them when busting brush or humping the mountains.

                      I already know what my elevation drops are, so it's easy enough to hold or just have my turret at whatever position I want it at, and zero out wit the zero stop if I need to.

                      I do like to confirm zero and get 50yd and 200yd data at the camp site if possible, which also gives us the opportunity to check the other rifles.

                      I also use scope cap charts as back-up, and cards. I deal with a lot of elevation change up here in the mountains (4400ft - 9200ft spread, with higher elevations possible as well), but my close-in drop will only change by about .1 mil for each 100yd increment within 500yds, and .2 mils at 600yds.

                      700yds will vary .4 mils between 4400-9200
                      800yds - .6 mils
                      900yds - .7 mils
                      1000yds - 1.0 mils

                      The saying, "Beware of a man who owns only one rifle that shoots a lot." comes to mind. The more time I spend with one particular rifle without spending energy on diversification, the more my hit probability increases with that rifle.
                      NRA Basic, Pistol, Rifle, Shotgun, RSO

                      CCW, CQM, DM, Long Range Rifle Instructor

                      6.5 Grendel Reloading Handbooks & chamber brushes can be found here:

                      www.AR15buildbox.com

                      Comment

                      • Mopardoctor
                        Warrior
                        • Apr 2015
                        • 117

                        #12
                        I found that the come-ups with my 6.5 Grendel and my 30-06 w/168G TTSX are the same out to 300 yards. Saves a lot of confusion at close to medium ranges.

                        Mopar Doctor
                        Got Ammo?

                        Comment

                        • KingJD79
                          Unwashed
                          • Dec 2015
                          • 18

                          #13
                          Thanks for the info gents. Definitely a lot to digest.

                          Comment

                          • Drift
                            Warrior
                            • Nov 2014
                            • 509

                            #14
                            Like they were saying, PBR is probably the best way to go if you aren't using laser range finders or figuring out mils. . Let me convert this to American units for you. (1) First you decide how big the killzone of your intended pray animal is-say a 5 inch circle on a deer. (2) That means that if you shoot 2.5 inches high because you are too close to your target, or 2.5 inches low because you are to far, will still be in the same 5 inch kill zone. (3) you look up ballistic tables like Hornady has online and figure out how high or low your bullet will hit at a known distances (4) how aerodynamic (BC of )the bullet and its velocity will effect your max PBR-altitude and temp not so much for regular hunting. (5) HINT if you set your rifle to hit 2.5-2.6 inches high@100 yards you will probably be very happy with the results. (6)Beyond 400 yards its probably best to tape to the side of the rifle the expected drop that you looked up on the ballistic tables.

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