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<blockquote data-quote="Jeff Heeg osoh" data-source="post: 2245903" data-attributes="member: 111250"><p>Just a couple things that will affect end results</p><p></p><p>1st the scope.</p><p>we will setup at a measured 100 yards and hang a 72" carpenters rule that is plumb vertical. Then we will lock a block down in a vice that has a picatinny rail mounted to it and a scope we want to check mounted to the rail. I still used a comparator and marked the Mils on the rule as well as check the inches used for a moa scope, its amazing that some carpenter rules are not as accurate as you would think. Then we will crank the turrets and check the actual travel of the cross hairs - retical and record the measurements in 10 mil increments or the actual travel in moa versus what was dialed. The tooling in the threads on the scope turretts is what causes a difference and we have seen this in about any high end scope manufactured. This seems faster, cheaper and more accurate then shooting rounds off at a box target but most importantly it eliminates any error from accuracy in the shooter and or ammo. Most Balistics programs have a scope correction factor that you can now enter in what you found out after doing this test. Note it is also nice to see if your retical tracks straight with the plumbed carpenters rule when dialing it up and down.</p><p></p><p>BC and manufactures ratings</p><p>Two things affect what a honest manufacturer rated BC is versus yours.</p><p>The fps speed they were tested at the manufacture facility versus yours will change BC values.</p><p>Most importantly the groves in the barrel will distort a bullet differently from one barrel to the next when fired and the end result is the grooves in the bullet now can be more distorted and will effect the BC efficiency of the bullet versus if it was shot from another rifle.</p><p></p><p>The DA will also throw a wrench in the gears as far as your impacts versus what was posted on a label or from one day to the next or morning versus hot afternoons after you think you have everything figured out.</p><p></p><p>For us once we have calibrated the scope travel in the retical versus what was dialed then entered that in the scope correction values on the program we will shoot groups at 800 or 1000 and tweak the BC value in the program to make the new info on what to dial make sense with the impacts. For some folks this may mean shooting groups at 300 or 500 - wherever they can get good feedback on a calm overcast day that is within their skill level with good feedback. The overcast and calm days do help with wind issues pushing a bullet and less mirage distorting the target.</p><p></p><p>Hope this helped some.</p><p>JH</p></blockquote><p></p>
[QUOTE="Jeff Heeg osoh, post: 2245903, member: 111250"] Just a couple things that will affect end results 1st the scope. we will setup at a measured 100 yards and hang a 72” carpenters rule that is plumb vertical. Then we will lock a block down in a vice that has a picatinny rail mounted to it and a scope we want to check mounted to the rail. I still used a comparator and marked the Mils on the rule as well as check the inches used for a moa scope, its amazing that some carpenter rules are not as accurate as you would think. Then we will crank the turrets and check the actual travel of the cross hairs - retical and record the measurements in 10 mil increments or the actual travel in moa versus what was dialed. The tooling in the threads on the scope turretts is what causes a difference and we have seen this in about any high end scope manufactured. This seems faster, cheaper and more accurate then shooting rounds off at a box target but most importantly it eliminates any error from accuracy in the shooter and or ammo. Most Balistics programs have a scope correction factor that you can now enter in what you found out after doing this test. Note it is also nice to see if your retical tracks straight with the plumbed carpenters rule when dialing it up and down. BC and manufactures ratings Two things affect what a honest manufacturer rated BC is versus yours. The fps speed they were tested at the manufacture facility versus yours will change BC values. Most importantly the groves in the barrel will distort a bullet differently from one barrel to the next when fired and the end result is the grooves in the bullet now can be more distorted and will effect the BC efficiency of the bullet versus if it was shot from another rifle. The DA will also throw a wrench in the gears as far as your impacts versus what was posted on a label or from one day to the next or morning versus hot afternoons after you think you have everything figured out. For us once we have calibrated the scope travel in the retical versus what was dialed then entered that in the scope correction values on the program we will shoot groups at 800 or 1000 and tweak the BC value in the program to make the new info on what to dial make sense with the impacts. For some folks this may mean shooting groups at 300 or 500 - wherever they can get good feedback on a calm overcast day that is within their skill level with good feedback. The overcast and calm days do help with wind issues pushing a bullet and less mirage distorting the target. Hope this helped some. JH [/QUOTE]
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