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<blockquote data-quote="Jon A" data-source="post: 52012" data-attributes="member: 319"><p>Monte, </p><p></p><p>I'm not seeing a 155 Scenar on Lapua's site. What is the advertised BC? While comparing the other weights of Scenars with SMK's, they seem to be fairly similar weight for weight. If they make a 155 with a similar BC to the 175 SMK it comes from the shape (probably a really long--13 caliber or more--secant ogive with a very sharp tip). If they filled the nose full of lead without changing the shape it would have an even better BC.</p><p></p><p>Texas, </p><p></p><p>Using the same materials the bullets would have all the same weight/length limitations. But you could make things that aren't on the market. A long 220-240 grain bonded, partitioned bullet with a high BC wouln't sell enough for a manufacturer to produce. But wouldn't it be cool? Using Tungsten can make much heavier bullets with the same length. Don't get me wrong, I'm not ready to try this tomorrow, I've just thought it would be a fun thing to do "someday." To be able to make a bullet that isn't on the market...to feel the same satisfaction knowing you made the bullets as you feel shooting reloaded ammo instead of factory ammo. It just seems like a fun hobby if I ever get the spare time.</p><p></p><p>Ian,</p><p></p><p>Sorry about being a numbers guy...that's just the way I am. <img src="http://images/icons/grin.gif" alt="" class="fr-fic fr-dii fr-draggable " style="" /> Time of flight is important, but more for trajectory than wind drift...let me try to just give you a real world example to show what I'm talking about.</p><p></p><p>Say you have a 300 RUM with a long barrel. You can shoot the 180 SMK's at 3450, and the 240's at 2950.</p><p></p><p>Trajectory-wise, the 180's beat the 240's all the way out to 1900 yds before the 240's "catch up." So if you only hunt at less than 1900, the 180 is flatter shooting. The added velocity "makes up" for the lower BC as far as trajectory is concerned. This would be very adventagous to a "regular" hunter that doesn't use a rangefinder and just wants his rifle to be really flat shooting. In fact, even a lighter bullet will do much better at closer ranges for such a hunter.</p><p></p><p>But you have a rangefinder. You will know the range within +/-1 yd. You have verified your drop chart and it will be accurate to your maximum range. The "flat shooting" advantage kind of goes away. A couple of extra clicks on your scope are the only difference.</p><p></p><p>What's the biggest worry after that? Wind drift. The 240's drift less from the beginning. At only 300 yds they drift almost an inch less in a 10 MPH crosswind. At 500, the advantage is 2.5". At 800 the advantage is more than 7". At 1000 the advantage is over a foot. And on and on. If you can correct for trajectory, you'll be more accurate with the 240 unless you are shooting in a vaccuum. The added velocity of the 180's didn't "make up" for the lower BC here. The 240's will always drift less.</p><p></p><p>Then there's the energy. In this example, the 180's actually start out with 120 ft-lbs more. But that advantage is gone before 100 yds. At 500, the 240's have the advantage, 3100 to 2680. At 800 it's 2400 to 1870. At 1000 yds it is 2000 to 1440. That's enough difference to make a difference in killing power.</p><p></p><p>The 180's shoot flatter. But you can adjust for that very accurately. The 240's resist the wind better (much harder to adjust for) and hit much harder at all ranges.</p><p></p><p>Anyway, I hope that gets the point I was trying to make accross a bit better than theoretical ramblings....</p></blockquote><p></p>
[QUOTE="Jon A, post: 52012, member: 319"] Monte, I'm not seeing a 155 Scenar on Lapua's site. What is the advertised BC? While comparing the other weights of Scenars with SMK's, they seem to be fairly similar weight for weight. If they make a 155 with a similar BC to the 175 SMK it comes from the shape (probably a really long--13 caliber or more--secant ogive with a very sharp tip). If they filled the nose full of lead without changing the shape it would have an even better BC. Texas, Using the same materials the bullets would have all the same weight/length limitations. But you could make things that aren't on the market. A long 220-240 grain bonded, partitioned bullet with a high BC wouln't sell enough for a manufacturer to produce. But wouldn't it be cool? Using Tungsten can make much heavier bullets with the same length. Don't get me wrong, I'm not ready to try this tomorrow, I've just thought it would be a fun thing to do "someday." To be able to make a bullet that isn't on the market...to feel the same satisfaction knowing you made the bullets as you feel shooting reloaded ammo instead of factory ammo. It just seems like a fun hobby if I ever get the spare time. Ian, Sorry about being a numbers guy...that's just the way I am. [img]images/icons/grin.gif[/img] Time of flight is important, but more for trajectory than wind drift...let me try to just give you a real world example to show what I'm talking about. Say you have a 300 RUM with a long barrel. You can shoot the 180 SMK's at 3450, and the 240's at 2950. Trajectory-wise, the 180's beat the 240's all the way out to 1900 yds before the 240's "catch up." So if you only hunt at less than 1900, the 180 is flatter shooting. The added velocity "makes up" for the lower BC as far as trajectory is concerned. This would be very adventagous to a "regular" hunter that doesn't use a rangefinder and just wants his rifle to be really flat shooting. In fact, even a lighter bullet will do much better at closer ranges for such a hunter. But you have a rangefinder. You will know the range within +/-1 yd. You have verified your drop chart and it will be accurate to your maximum range. The "flat shooting" advantage kind of goes away. A couple of extra clicks on your scope are the only difference. What's the biggest worry after that? Wind drift. The 240's drift less from the beginning. At only 300 yds they drift almost an inch less in a 10 MPH crosswind. At 500, the advantage is 2.5". At 800 the advantage is more than 7". At 1000 the advantage is over a foot. And on and on. If you can correct for trajectory, you'll be more accurate with the 240 unless you are shooting in a vaccuum. The added velocity of the 180's didn't "make up" for the lower BC here. The 240's will always drift less. Then there's the energy. In this example, the 180's actually start out with 120 ft-lbs more. But that advantage is gone before 100 yds. At 500, the 240's have the advantage, 3100 to 2680. At 800 it's 2400 to 1870. At 1000 yds it is 2000 to 1440. That's enough difference to make a difference in killing power. The 180's shoot flatter. But you can adjust for that very accurately. The 240's resist the wind better (much harder to adjust for) and hit much harder at all ranges. Anyway, I hope that gets the point I was trying to make accross a bit better than theoretical ramblings.... [/QUOTE]
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