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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
going from 600 to 800 yards
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<blockquote data-quote="Buffalobob" data-source="post: 138459" data-attributes="member: 8"><p>Ok Rufous, I will let other deal with ES being as I don't know anything about it and I will just give you a basic course in long range trajectory.</p><p></p><p>You should go out and dial your gun in for what ever range you would like to shoot and then for a couple of hundred yards more. So if you wanted to shoot tadpoles out to 1000 yards you would have a dial in to 1200 yards. If you want to shoot possums at 800 yards you should dial in to 1000 yards.</p><p></p><p>The dialin should begin at some recognizable point – say 100 yards for a beginner and you should shoot the gun into the target for every two hundred yards out to 1200 yards. Typically I shoot a group at a distance and then fine adjust and reshoot to verify the adjustment and then move on to the next distance. Close in such as 100, 300 and 500 yds I may only shoot 1 or two rounds as a group and as the distance increases I will increase the number of bullets in the group.</p><p></p><p>The barrel must be kept cool during all of this shooting and somewhat clean. The temperature should be not freezing cold nor blazing hot. Wind should be almost none. I try to start shooting at first light and really don't like to shoot once the sun gets on the target because I have trouble judging mirage. This means several sessions to get a good bullet dialin. All of the bullets should be from the same loading so there is nothing different in the cartridges.</p><p></p><p>No then, you should have a notebook of some kind and in that you will record the drops for every distance you shot. This is critical that you keep this information in a safe place so you can get at it again.</p><p></p><p>If you have a chronograph, that is great. If it is accurate that is even better. If you trust what it says, you shouldn't. You now have a muzzle velocity and six or seven drops along the trajectory of the bullet. You have the manufacturers Ballistic Coefficient. In a perfect world you could simply take a ballistic program and input the muzzle velocity, BC, temperature, altitude and other data and the program would compute a trajectory that would match the drops you shot. It is unlikely that your real world data will match the data from the computer. So at this time you must start a guessing game. If you adjust the bullet BC to a lower value then the drops will increase. If you adjust it to a higher value drops will decrease. What I expect you will find is that you cannot match your real data by adjusting only the BC. You should then begin tweaking the muzzle velocity at BC values that were close to your real data. Remember that it is more important to match the further out data points than the closer data points if you are shooting at an animal. This is why you shoot way past where you plan of shooting an animal – to make the longer range part of the curve more accurate. Once you have a good match to your real data you print out what you have. What you print out must have the final muzzle velocity and final BC you used to duplicate the curve.</p><p></p><p>So you now have a drop chart but you get tired of shooting Walla Walla bingbangs and decide to go to Colorado and hunt up high in the snow. Take you computer and the information that produced your drop chart and change only temperature and elevation. Do not change BC nor the input muzzle velocity (I don't care what the "real" muzzle velocity is). This will shift the shape of the trajectory by only the factors that have physically changed.</p><p></p><p>Finally, when you get to Colorado up in the snow, verify your zero and verify at least one drop at a long distance. If they don't match than adjust your drop chart again.</p><p></p><p>In all of this you should see that I give preference to what I see my bullets do. Every time, I will believe my bullets over my computer or any other electronic device. Bullets kill elk, computers kill time.</p></blockquote><p></p>
[QUOTE="Buffalobob, post: 138459, member: 8"] Ok Rufous, I will let other deal with ES being as I don’t know anything about it and I will just give you a basic course in long range trajectory. You should go out and dial your gun in for what ever range you would like to shoot and then for a couple of hundred yards more. So if you wanted to shoot tadpoles out to 1000 yards you would have a dial in to 1200 yards. If you want to shoot possums at 800 yards you should dial in to 1000 yards. The dialin should begin at some recognizable point – say 100 yards for a beginner and you should shoot the gun into the target for every two hundred yards out to 1200 yards. Typically I shoot a group at a distance and then fine adjust and reshoot to verify the adjustment and then move on to the next distance. Close in such as 100, 300 and 500 yds I may only shoot 1 or two rounds as a group and as the distance increases I will increase the number of bullets in the group. The barrel must be kept cool during all of this shooting and somewhat clean. The temperature should be not freezing cold nor blazing hot. Wind should be almost none. I try to start shooting at first light and really don’t like to shoot once the sun gets on the target because I have trouble judging mirage. This means several sessions to get a good bullet dialin. All of the bullets should be from the same loading so there is nothing different in the cartridges. No then, you should have a notebook of some kind and in that you will record the drops for every distance you shot. This is critical that you keep this information in a safe place so you can get at it again. If you have a chronograph, that is great. If it is accurate that is even better. If you trust what it says, you shouldn’t. You now have a muzzle velocity and six or seven drops along the trajectory of the bullet. You have the manufacturers Ballistic Coefficient. In a perfect world you could simply take a ballistic program and input the muzzle velocity, BC, temperature, altitude and other data and the program would compute a trajectory that would match the drops you shot. It is unlikely that your real world data will match the data from the computer. So at this time you must start a guessing game. If you adjust the bullet BC to a lower value then the drops will increase. If you adjust it to a higher value drops will decrease. What I expect you will find is that you cannot match your real data by adjusting only the BC. You should then begin tweaking the muzzle velocity at BC values that were close to your real data. Remember that it is more important to match the further out data points than the closer data points if you are shooting at an animal. This is why you shoot way past where you plan of shooting an animal – to make the longer range part of the curve more accurate. Once you have a good match to your real data you print out what you have. What you print out must have the final muzzle velocity and final BC you used to duplicate the curve. So you now have a drop chart but you get tired of shooting Walla Walla bingbangs and decide to go to Colorado and hunt up high in the snow. Take you computer and the information that produced your drop chart and change only temperature and elevation. Do not change BC nor the input muzzle velocity (I don’t care what the “real” muzzle velocity is). This will shift the shape of the trajectory by only the factors that have physically changed. Finally, when you get to Colorado up in the snow, verify your zero and verify at least one drop at a long distance. If they don’t match than adjust your drop chart again. In all of this you should see that I give preference to what I see my bullets do. Every time, I will believe my bullets over my computer or any other electronic device. Bullets kill elk, computers kill time. [/QUOTE]
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