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Rifles, Reloading, Optics, Equipment
Reloading
7mm Rem mag, 168gr vld & retumbo load data?
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<blockquote data-quote="KYpatriot" data-source="post: 1149544" data-attributes="member: 48028"><p>Its not ES and SD MAY matter, they absolutely DO matter, and can matter as much as groups do if you are shooting long range. </p><p></p><p>If I implied groups dont matter, i dudnt mean to, of course they do.</p><p></p><p>I was pointing out that it can be tempting to ignore the chrony data and go for the .3 inch group instead of the .6 group. In cases where the ES is significantly better, it may not be wise. That was my experience...slightly better groups with retumbo, but much better ES with H1000. Long range results on target bore out what i already knew from the chrony data.</p><p></p><p>Consider a 338lapua, with a 300 grain SMK. A formidable long range setup. At 2800 fps it drops 274inches in the conditions last in my ballistic calculator. At 2750 it is 286inches. Roughly 1.2 moa. Its not difficult at all to see 50fps spreads in large cases of slow powder if you arent paying attention to it. I am a meticulous reloader, weighing to the kernal, little to no runout and ogive to lands consistent within .001, and i saw as much as 80 with retumbo. </p><p></p><p>Im just saying that group size is only half the equation unless you only shoot at closer ranges. Its also surprising how much velocity spread you can have in an otherwise excellent short range group. You would think that good groups would also have consistent velocities, but often that isnt true. It makes no sense to tune a group to sub moa precision and then accept velocity spreads that will definitely result in over moa groups at range.</p><p></p><p>It is also maddening to get small ES sometimes. I think it is much easier to tune for groups than it is velocity consistency.</p></blockquote><p></p>
[QUOTE="KYpatriot, post: 1149544, member: 48028"] Its not ES and SD MAY matter, they absolutely DO matter, and can matter as much as groups do if you are shooting long range. If I implied groups dont matter, i dudnt mean to, of course they do. I was pointing out that it can be tempting to ignore the chrony data and go for the .3 inch group instead of the .6 group. In cases where the ES is significantly better, it may not be wise. That was my experience...slightly better groups with retumbo, but much better ES with H1000. Long range results on target bore out what i already knew from the chrony data. Consider a 338lapua, with a 300 grain SMK. A formidable long range setup. At 2800 fps it drops 274inches in the conditions last in my ballistic calculator. At 2750 it is 286inches. Roughly 1.2 moa. Its not difficult at all to see 50fps spreads in large cases of slow powder if you arent paying attention to it. I am a meticulous reloader, weighing to the kernal, little to no runout and ogive to lands consistent within .001, and i saw as much as 80 with retumbo. Im just saying that group size is only half the equation unless you only shoot at closer ranges. Its also surprising how much velocity spread you can have in an otherwise excellent short range group. You would think that good groups would also have consistent velocities, but often that isnt true. It makes no sense to tune a group to sub moa precision and then accept velocity spreads that will definitely result in over moa groups at range. It is also maddening to get small ES sometimes. I think it is much easier to tune for groups than it is velocity consistency. [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Reloading
7mm Rem mag, 168gr vld & retumbo load data?
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