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Long Range Hunting & Shooting
What do you think of the 6.5 WBY RPM ?
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<blockquote data-quote="John Polk" data-source="post: 1736019" data-attributes="member: 109560"><p>Sorry Shep, I don't know what numbers you are feeding into your calculator, but they certainly do not match mine. I am up in the mountains of northern New Mexico at the moment or I would attach them, but that can be done later.</p><p>First, bullets derive their energy from the amount of powder in the case behind them which, when ignited, expels the bullets at high speed. The .270 Winchester case holds between 62 and 64 grains of water whereas the 264 Creedmoor case holds between 46 and 49 grains of water. To say that the smaller cartridge outperforms the larger one defies chemistry. The .270 Winchester has several bullet weights for specific performance purposes. I choose 130-grain bullet, which is analogous to the 120 grain .264 bullet, because I want to have it arrive as quickly as possible on the game I am hunting out to 500 - 600 yards. I'd love to see a chronograph print-out of a .264 Creedmoor chambered rifle launching a 147gr. bullet at 2850 fps at comparable pressures to my launching a 130 bullet from my rifle at 3180 -3200 fps. If I were to do a pure long-range comparison of the .270 Win. to the 6.5 Creedmoor I would use the 140 and 150 Nosler Accubonds with their much higher ballistic coefficients. This might be solved if there is a disparity between barrel lengths - mine are 22' and 24 ".</p><p>Most bullet manufacturers say 1800 fps is the minimum speed for reliable mushrooming of modern bullets so let's agree on that as the bottom line of our discussion. I attach a table of the deceleration of a 130 gr. .270Win. bullet over 1000 yards and you show me where your calculator says your .264 bullet catches up with my .270 bullet and how long it takes to equalize the time differential between the two bullets..</p><p><strong>5300ft Elevation</strong></p><p>Distance, Bullet speed, f/s Energy, ft-lb.</p><p>yards</p><p>0.0 3152.9 2869.4</p><p>100.0 2961.9 2532.4</p><p>200.0 2780.8 2232.2</p><p>300.0 2607.0 1961.7</p><p>400.0 2440.3 1718.9</p><p>500.0 2280.2 1500.8</p><p>800.0 1840.6 977.8 </p><p>900.0 1706.7 840.8</p><p>1000.0 1579.4 720.0</p></blockquote><p></p>
[QUOTE="John Polk, post: 1736019, member: 109560"] Sorry Shep, I don't know what numbers you are feeding into your calculator, but they certainly do not match mine. I am up in the mountains of northern New Mexico at the moment or I would attach them, but that can be done later. First, bullets derive their energy from the amount of powder in the case behind them which, when ignited, expels the bullets at high speed. The .270 Winchester case holds between 62 and 64 grains of water whereas the 264 Creedmoor case holds between 46 and 49 grains of water. To say that the smaller cartridge outperforms the larger one defies chemistry. The .270 Winchester has several bullet weights for specific performance purposes. I choose 130-grain bullet, which is analogous to the 120 grain .264 bullet, because I want to have it arrive as quickly as possible on the game I am hunting out to 500 - 600 yards. I'd love to see a chronograph print-out of a .264 Creedmoor chambered rifle launching a 147gr. bullet at 2850 fps at comparable pressures to my launching a 130 bullet from my rifle at 3180 -3200 fps. If I were to do a pure long-range comparison of the .270 Win. to the 6.5 Creedmoor I would use the 140 and 150 Nosler Accubonds with their much higher ballistic coefficients. This might be solved if there is a disparity between barrel lengths - mine are 22' and 24 ". Most bullet manufacturers say 1800 fps is the minimum speed for reliable mushrooming of modern bullets so let's agree on that as the bottom line of our discussion. I attach a table of the deceleration of a 130 gr. .270Win. bullet over 1000 yards and you show me where your calculator says your .264 bullet catches up with my .270 bullet and how long it takes to equalize the time differential between the two bullets.. [B]5300ft Elevation[/B] Distance, Bullet speed, f/s Energy, ft-lb. yards 0.0 3152.9 2869.4 100.0 2961.9 2532.4 200.0 2780.8 2232.2 300.0 2607.0 1961.7 400.0 2440.3 1718.9 500.0 2280.2 1500.8 800.0 1840.6 977.8 900.0 1706.7 840.8 1000.0 1579.4 720.0 [/QUOTE]
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What do you think of the 6.5 WBY RPM ?
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