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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
New Oehler 35P, New skyscreen rail, First Test Data
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<blockquote data-quote="Pdvdh" data-source="post: 523330" data-attributes="member: 4191"><p><strong>Some 985 Yard Data & G7 BC Determination</strong></p><p></p><p>Another data set to digest. I shot @ 985 yards last weekend and was able to place some bullets over the skyscreens. I shot five times and received data on four of those five shots. </p><p></p><p>One shot passed wide and resulted in no velocity data. </p><p></p><p>I received partial data on shot #2, which passed slightly wide of the center line of the skyscreens. This likely caused a 20-21 feet/sec difference in the velocities recorded on the Oehler 33 and Oehler 35P, and no reading from the PACT. I conclude that chronographs are less likely to provide accurate data when the bullets aren't centered over the skyscreens. </p><p></p><p>The other three shots were dead center over the skyscreens. On shot #4, the last shot of the day, the light was fading and the PACT failed to record any velocity. I've experienced this several times over the past three years. The Oehlers continue to record velocity a bit longer than the PACT in fading light. </p><p></p><p>Here's the data I collected: </p><p></p><p>Shot . Oehler 33 . . Oehler 35Primary . . Oehler 35Proof . . PACT PC2</p><p>. 1 . . <strong>1618 . . . . . . 1619 . . . . . . . . . . .1620</strong> . . . . . . . . 1617</p><p>. 2 . . 1670 . . . . . . 1649. . . . . . . . . . 1651 . . . . . . . . .-NR-. . . . Poor agreement from the Oehlers. No reading from PACT. Discard these data.</p><p>. 3 . . <strong>1627 . . . . . . 1630 . . . . . . . . . . .1627</strong> . . . . . . . . 1630</p><p><u>. 4 . . <strong>1638 . . . . . . 1642 . . . . . . . . . . .1640</strong></u> . . . . . . . . -NR-. . . . No reading from PACT due to low light conditions.</p><p><strong>Avg. . 1628 . . . . . . 1630 . . . . . . . . . . .1629</strong></p><p></p><p>I had already determined the average Muzzle Velocity of this load at 3074 fps. The primary purpose of this chronograph session was to establish an accurate BC value for this bullet by obtaining 985 yard velocity data. Other reasons were to record 985 yard drops and accuracy.</p><p></p><p>Shot #2 yielded poor agreement between the Oehler 33 and the Oehler 35P, and no reading from the PACT. When I'm getting good data, the velocities will record within 5 feet/sec. Often within 2 or 3 feet/sec. So I didn't include shot #2 velocity data while determining my average 985 yard velocity. And since the PACT only recorded two velocities I chose to only use the <strong>bolded</strong> values from the Oehlers to calculate average V985s. I then used the average of these 3 average velocity values - <strong>1629</strong> fps - as my average 985 yard velocity. I used LoadBase 3.0 ballistic software to calculate a G7 BC value of 0.289. This G7 value is referenced to ICAO environmental conditions: 29.92 inches/Hg, 59F, and 0%RH. </p><p></p><p>LRH Forum member '<strong>elkoholic</strong>' manufactured these bullets. He had determined a G7 BC value of 0.308, but his value was obtained from measured drops while shooting at an elevation of 2500 feet. So out of curiosity, I used LoadBase 3.0 to calculate a 985 yard velocity at the 2500 foot elevation, and then determined a G7 BC value of 0.311 based on that higher downrange velocity. Very close to the 0.308 G7 elkaholic had determined through measurement of downrange drops. elkaholic has probably shot and measured a lot of downrange drops. </p><p></p><p>These 190 grain SXRs are the most accurate bullets I've ever shot out of my 300 Win Mag. My very first load is providing significantly better accuracy than I've ever obtained with Berger 210 VLDs - even after extensive VLD load development efforts.</p></blockquote><p></p>
[QUOTE="Pdvdh, post: 523330, member: 4191"] [b]Some 985 Yard Data & G7 BC Determination[/b] Another data set to digest. I shot @ 985 yards last weekend and was able to place some bullets over the skyscreens. I shot five times and received data on four of those five shots. One shot passed wide and resulted in no velocity data. I received partial data on shot #2, which passed slightly wide of the center line of the skyscreens. This likely caused a 20-21 feet/sec difference in the velocities recorded on the Oehler 33 and Oehler 35P, and no reading from the PACT. I conclude that chronographs are less likely to provide accurate data when the bullets aren't centered over the skyscreens. The other three shots were dead center over the skyscreens. On shot #4, the last shot of the day, the light was fading and the PACT failed to record any velocity. I've experienced this several times over the past three years. The Oehlers continue to record velocity a bit longer than the PACT in fading light. Here's the data I collected: Shot . Oehler 33 . . Oehler 35Primary . . Oehler 35Proof . . PACT PC2 . 1 . . [B]1618 . . . . . . 1619 . . . . . . . . . . .1620[/B] . . . . . . . . 1617 . 2 . . 1670 . . . . . . 1649. . . . . . . . . . 1651 . . . . . . . . .-NR-. . . . Poor agreement from the Oehlers. No reading from PACT. Discard these data. . 3 . . [B]1627 . . . . . . 1630 . . . . . . . . . . .1627[/B] . . . . . . . . 1630 [U]. 4 . . [B]1638 . . . . . . 1642 . . . . . . . . . . .1640[/B][/U] . . . . . . . . -NR-. . . . No reading from PACT due to low light conditions. [B]Avg. . 1628 . . . . . . 1630 . . . . . . . . . . .1629[/B] I had already determined the average Muzzle Velocity of this load at 3074 fps. The primary purpose of this chronograph session was to establish an accurate BC value for this bullet by obtaining 985 yard velocity data. Other reasons were to record 985 yard drops and accuracy. Shot #2 yielded poor agreement between the Oehler 33 and the Oehler 35P, and no reading from the PACT. When I'm getting good data, the velocities will record within 5 feet/sec. Often within 2 or 3 feet/sec. So I didn't include shot #2 velocity data while determining my average 985 yard velocity. And since the PACT only recorded two velocities I chose to only use the [B]bolded[/B] values from the Oehlers to calculate average V985s. I then used the average of these 3 average velocity values - [B]1629[/B] fps - as my average 985 yard velocity. I used LoadBase 3.0 ballistic software to calculate a G7 BC value of 0.289. This G7 value is referenced to ICAO environmental conditions: 29.92 inches/Hg, 59F, and 0%RH. LRH Forum member '[B]elkoholic[/B]' manufactured these bullets. He had determined a G7 BC value of 0.308, but his value was obtained from measured drops while shooting at an elevation of 2500 feet. So out of curiosity, I used LoadBase 3.0 to calculate a 985 yard velocity at the 2500 foot elevation, and then determined a G7 BC value of 0.311 based on that higher downrange velocity. Very close to the 0.308 G7 elkaholic had determined through measurement of downrange drops. elkaholic has probably shot and measured a lot of downrange drops. These 190 grain SXRs are the most accurate bullets I've ever shot out of my 300 Win Mag. My very first load is providing significantly better accuracy than I've ever obtained with Berger 210 VLDs - even after extensive VLD load development efforts. [/QUOTE]
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New Oehler 35P, New skyscreen rail, First Test Data
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