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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Conclusions from data?
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<blockquote data-quote="jmden" data-source="post: 126893" data-attributes="member: 1742"><p>I'm on the third firing of this 300RUM Rem brass and I believe that I've found that the third firing and on things seem to get a litte more consistent in terms of grouping and velocities--sound familiar to anyone?</p><p></p><p>At any rate, here's some chrono data (20ft. from muzzle) from an Oehler 33 at the range from a barrel that had three of the exact same rounds fired through it a couple of weeks ago and was left dirty. So cold, dirty barrel for first round. 200AB, 109g of US869, charges carefully weighed and generally very careful reloading. About 40 degree ambient.</p><p></p><p>1-3166</p><p>2-3244</p><p>3-3192</p><p>4-3205</p><p>5-3203</p><p>6-error</p><p>7-3211</p><p>8-3203</p><p>9-error</p><p>10-3234-started to rain</p><p>11-3240-rain</p><p>12-3196-rain let up considerably</p><p>13-3201</p><p></p><p>What concerns me is the lower velocity of the first round. To have more reliable data, I'd need to go to the range in the same conditions with a cold dirty barrel to check that 1st shot velocity, but at longer ranges that much drop in velocity on that first shot you're really relying on might spell trouble. Any thoughts on that data?</p><p></p><p>The second shot at 3244--not sure what that is all about. I wasn't real consistent with letting the barrel cool down or not during this string which is not typical of me but may have contributed to a couple of the higher numbers.</p><p></p><p>I'm thinking that the rain may have contributed to 10 and 11 being high. </p><p></p><p>I'm OK with the rest of the numbers. There's a great deal of folks on this board that have more experience than I and I'm hoping that someone might be able to make a little more sense out of the this data than I. Thank you!</p></blockquote><p></p>
[QUOTE="jmden, post: 126893, member: 1742"] I'm on the third firing of this 300RUM Rem brass and I believe that I've found that the third firing and on things seem to get a litte more consistent in terms of grouping and velocities--sound familiar to anyone? At any rate, here's some chrono data (20ft. from muzzle) from an Oehler 33 at the range from a barrel that had three of the exact same rounds fired through it a couple of weeks ago and was left dirty. So cold, dirty barrel for first round. 200AB, 109g of US869, charges carefully weighed and generally very careful reloading. About 40 degree ambient. 1-3166 2-3244 3-3192 4-3205 5-3203 6-error 7-3211 8-3203 9-error 10-3234-started to rain 11-3240-rain 12-3196-rain let up considerably 13-3201 What concerns me is the lower velocity of the first round. To have more reliable data, I'd need to go to the range in the same conditions with a cold dirty barrel to check that 1st shot velocity, but at longer ranges that much drop in velocity on that first shot you're really relying on might spell trouble. Any thoughts on that data? The second shot at 3244--not sure what that is all about. I wasn't real consistent with letting the barrel cool down or not during this string which is not typical of me but may have contributed to a couple of the higher numbers. I'm thinking that the rain may have contributed to 10 and 11 being high. I'm OK with the rest of the numbers. There's a great deal of folks on this board that have more experience than I and I'm hoping that someone might be able to make a little more sense out of the this data than I. Thank you! [/QUOTE]
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Conclusions from data?
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