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	<title>Daily Bulletin &#187; G7 Model</title>
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		<title>G1 vs. G7 Ballistic Coefficient Types &#8212; What You Should Know</title>
		<link>https://bulletin.accurateshooter.com/2026/05/g1-vs-g7-ballistic-coefficient-types-what-you-should-know/</link>
		<comments>https://bulletin.accurateshooter.com/2026/05/g1-vs-g7-ballistic-coefficient-types-what-you-should-know/#comments</comments>
		<pubDate>Thu, 28 May 2026 06:55:08 +0000</pubDate>
		<dc:creator><![CDATA[Editor]]></dc:creator>
				<category><![CDATA[Bullets, Brass, Ammo]]></category>
		<category><![CDATA[Tech Tip]]></category>
		<category><![CDATA[Ballistic Coefficient]]></category>
		<category><![CDATA[ballistics]]></category>
		<category><![CDATA[Berger Bullets]]></category>
		<category><![CDATA[Bryan Litz]]></category>
		<category><![CDATA[Bullet Drag]]></category>
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		<category><![CDATA[G1]]></category>
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		<guid isPermaLink="false">https://bulletin.accurateshooter.com/?p=72807</guid>
		<description><![CDATA[Over the past 12 months, this article was one of the TOP 20 most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. CLICK HERE to watch the video. The better, up-to-date [&#8230;]]]></description>
				<content:encoded><![CDATA[<p><img src="https://accurateshooter.net/pix/gmodel1801op.png" alt="G1 G7 BC drag models"></p>
<p><em>Over the past 12 months, this article was one of the <strong>TOP 20</strong> most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. <a href="https://youtu.be/gjzs79kDr6E" target="_blank">CLICK HERE</a> to watch the video.</em></p>
<p><img class="alignright" hspace='6' src="https://accurateshooter.net/Blog/g1g7entry.jpg">The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You&#8217;ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn&#8217;t mean you should select a G1 value simply because it is higher.</p>
<p>Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: &#8220;I went on the <a href="http://www.jbmballistics.com/ballistics/calculators/calculators.shtml" target="_blank">JBM Ballistics</a> website to use the web-based <a href="http://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi" target="new">Trajectory Calculator</a> and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?&#8221;</p>
<blockquote><p><font size="3" face="Tahoma">The simple answer is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.</font></p></blockquote>
<p><b>G1 vs. G7 Ballistic Coefficients &#8212; Which Is Right for You?</b><br />
G1 and G7 refer both refer to aerodynamic drag models based on particular &#8220;standard projectile&#8221; shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferable for flat-based bullets, while G7 is ordinarily a &#8220;better fit&#8221; for longer, boat-tailed bullets.</p>
<p><center><img src="https://accurateshooter.net/Blog/g1g7shape.png" alt="G1 G7 Ballistic coefficients"></center></p>
<p><img border="1" class="alignright" hspace="6" src="https://accurateshooter.net/Blog/blitzx200.jpg"><strong>Drag Models — G7 is better than G1 for Long-Range Bullets</strong><br />
Many ballistics programs still offer only the default G1 drag model. Bryan Litz, author of <a href="https://thescienceofaccuracy.com/store/" target="_blank">Applied Ballistics for Long Range Shooting</a>, believes the G7 standard is preferrable for long-range, low-drag bullets: “Part of the reason there is so much ‘slop’ in advertised BCs is because they&#8217;re referenced to the G1 standard which is very speed sensitive. The G7 standard is more appropriate for long range bullets. Here&#8217;s the results of my testing on two low-drag, long-range boat-tail bullets, so you can see how the G1 and G7 Ballistic coefficients compare:</p>
<p>G1 BCs, averaged between 1500 fps and 3000 fps:<br />
Berger 180 VLD: 0.659 lb/in²<br />
JLK 180: 0.645 lb/in²</p>
<p>The reason the BC for the JLK is less is mostly because the meplat was significantly larger on the particular lot that I tested (0.075″ vs 0.059″; see attached drawings).</p>
<p>For bullets like these, it&#8217;s much better to use the G7 standard. The following BCs are referenced to the G7 standard, and are constant for all speeds.</p>
<p>G7 BCs:<br />
Berger 180 VLD: 0.337 lb/in²<br />
JLK 180: 0.330 lb/in²</p>
<p>Many modern ballistics programs, including the free online <a href="https://www.jbmballistics.com/ballistics/calculators/calculators.shtml" target="_blank">JBM Ballistics Program</a>, are able to use BCs referenced to G7 standards. When available, these BCs are more appropriate for long range bullets, according to Bryan.</p>
<p>[Editor&#8217;s NOTE: BCs are normally reported simply as an 0.XXX number. The lb/in² tag applies to all BCs, but is commonly left off for simplicity.]<br />
<font size="1" color="ffffff">This article is copyright 2026 AccurateShooter.com. No 3rd Party republication of this article is allowed without advance approval and payment of licensing fees.</font></p>
]]></content:encoded>
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		</item>
		<item>
		<title>G1 vs. G7 Ballistic Coefficient Types &#8212; What You Need to Know</title>
		<link>https://bulletin.accurateshooter.com/2025/06/g1-vs-g7-ballistic-coefficient-types-what-you-need-to-know/</link>
		<comments>https://bulletin.accurateshooter.com/2025/06/g1-vs-g7-ballistic-coefficient-types-what-you-need-to-know/#comments</comments>
		<pubDate>Thu, 26 Jun 2025 09:12:09 +0000</pubDate>
		<dc:creator><![CDATA[Editor]]></dc:creator>
				<category><![CDATA[Bullets, Brass, Ammo]]></category>
		<category><![CDATA[Reloading]]></category>
		<category><![CDATA[Tech Tip]]></category>
		<category><![CDATA[Ballistic Coefficient]]></category>
		<category><![CDATA[ballistics]]></category>
		<category><![CDATA[Berger Bullets]]></category>
		<category><![CDATA[Bryan Litz]]></category>
		<category><![CDATA[Bullet Drag]]></category>
		<category><![CDATA[Drag Model]]></category>
		<category><![CDATA[G1]]></category>
		<category><![CDATA[G7]]></category>
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		<guid isPermaLink="false">http://bulletin.accurateshooter.com/?p=71634</guid>
		<description><![CDATA[Over the past 12 months, this article was one of the TOP 20 most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. CLICK HERE to watch the video. The better, up-to-date [&#8230;]]]></description>
				<content:encoded><![CDATA[<p><img src="https://accurateshooter.net/pix/gmodel1801op.png" alt="G1 G7 BC drag models"></p>
<p><em>Over the past 12 months, this article was one of the <strong>TOP 20</strong> most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. <a href="https://youtu.be/gjzs79kDr6E" target="_blank">CLICK HERE</a> to watch the video.</em></p>
<p><img class="alignright" hspace='6' src="https://accurateshooter.net/Blog/g1g7entry.jpg">The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You&#8217;ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn&#8217;t mean you should select a G1 value simply because it is higher.</p>
<p>Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: &#8220;I went on the <a href="http://www.jbmballistics.com/ballistics/calculators/calculators.shtml" target="_blank">JBM Ballistics</a> website to use the web-based <a href="http://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi" target="new">Trajectory Calculator</a> and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?&#8221;</p>
<blockquote><p><font size="3" face="Tahoma">The simple answer is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.</font></p></blockquote>
<p><b>G1 vs. G7 Ballistic Coefficients &#8212; Which Is Right for You?</b><br />
G1 and G7 refer both refer to aerodynamic drag models based on particular &#8220;standard projectile&#8221; shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferable for flat-based bullets, while G7 is ordinarily a &#8220;better fit&#8221; for longer, boat-tailed bullets.</p>
<p><center><img src="https://accurateshooter.net/Blog/g1g7shape.png" alt="G1 G7 Ballistic coefficients"></center></p>
<p><img border="1" class="alignright" hspace="6" src="https://accurateshooter.net/Blog/blitzx200.jpg"><strong>Drag Models — G7 is better than G1 for Long-Range Bullets</strong><br />
Many ballistics programs still offer only the default G1 drag model. Bryan Litz, author of <a href="https://thescienceofaccuracy.com/store/" target="_blank">Applied Ballistics for Long Range Shooting</a>, believes the G7 standard is preferrable for long-range, low-drag bullets: “Part of the reason there is so much ‘slop’ in advertised BCs is because they&#8217;re referenced to the G1 standard which is very speed sensitive. The G7 standard is more appropriate for long range bullets. Here&#8217;s the results of my testing on two low-drag, long-range boat-tail bullets, so you can see how the G1 and G7 Ballistic coefficients compare:</p>
<p>G1 BCs, averaged between 1500 fps and 3000 fps:<br />
Berger 180 VLD: 0.659 lb/in²<br />
JLK 180: 0.645 lb/in²</p>
<p>The reason the BC for the JLK is less is mostly because the meplat was significantly larger on the particular lot that I tested (0.075″ vs 0.059″; see attached drawings).</p>
<p>For bullets like these, it&#8217;s much better to use the G7 standard. The following BCs are referenced to the G7 standard, and are constant for all speeds.</p>
<p>G7 BCs:<br />
Berger 180 VLD: 0.337 lb/in²<br />
JLK 180: 0.330 lb/in²</p>
<p>Many modern ballistics programs, including the free online <a href="https://www.jbmballistics.com/ballistics/calculators/calculators.shtml" target="_blank">JBM Ballistics Program</a>, are able to use BCs referenced to G7 standards. When available, these BCs are more appropriate for long range bullets, according to Bryan.</p>
<p>[Editor&#8217;s NOTE: BCs are normally reported simply as an 0.XXX number. The lb/in² tag applies to all BCs, but is commonly left off for simplicity.]<br />
<font size="1" color="ffffff">This article is copyright 2023 AccurateShooter.com. No 3rd Party republication of this article is allowed without advance approval and payment of licensing fees.</font></p>
]]></content:encoded>
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		</item>
		<item>
		<title>G1 vs. G7 Ballistic Coefficients &#8212; What You Need to Know</title>
		<link>https://bulletin.accurateshooter.com/2024/06/g1-vs-g7-ballistic-coefficients-what-you-need-to-know-2/</link>
		<comments>https://bulletin.accurateshooter.com/2024/06/g1-vs-g7-ballistic-coefficients-what-you-need-to-know-2/#comments</comments>
		<pubDate>Tue, 18 Jun 2024 05:20:11 +0000</pubDate>
		<dc:creator><![CDATA[Editor]]></dc:creator>
				<category><![CDATA[- Articles]]></category>
		<category><![CDATA[Bullets, Brass, Ammo]]></category>
		<category><![CDATA[Tech Tip]]></category>
		<category><![CDATA[Ballistic Coefficient]]></category>
		<category><![CDATA[ballistics]]></category>
		<category><![CDATA[Berger Bullets]]></category>
		<category><![CDATA[Bryan Litz]]></category>
		<category><![CDATA[Bullet Drag]]></category>
		<category><![CDATA[Drag Model]]></category>
		<category><![CDATA[G1]]></category>
		<category><![CDATA[G7]]></category>
		<category><![CDATA[G7 Model]]></category>
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		<category><![CDATA[Trajectory]]></category>

		<guid isPermaLink="false">http://bulletin.accurateshooter.com/?p=65762</guid>
		<description><![CDATA[Over the past 12 months, this article was one of the TOP 20 most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. CLICK HERE to watch the video. The better, up-to-date [&#8230;]]]></description>
				<content:encoded><![CDATA[<p><img src="https://accurateshooter.net/pix/gmodel1801op.png" alt="G1 G7 BC drag models"></p>
<p><em>Over the past 12 months, this article was one of the <strong>TOP 20</strong> most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. <a href="https://youtu.be/gjzs79kDr6E" target="_blank">CLICK HERE</a> to watch the video.</em></p>
<p><img class="alignright" hspace='6' src="https://accurateshooter.net/Blog/g1g7entry.jpg">The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You&#8217;ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn&#8217;t mean you should select a G1 value simply because it is higher.</p>
<p>Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: &#8220;I went on the <a href="http://www.jbmballistics.com/ballistics/calculators/calculators.shtml" target="_blank">JBM Ballistics</a> website to use the web-based <a href="http://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi" target="new">Trajectory Calculator</a> and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?&#8221;</p>
<blockquote><p><font size="3" face="Tahoma">The simple answer is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.</font></p></blockquote>
<p><b>G1 vs. G7 Ballistic Coefficients &#8212; Which Is Right for You?</b><br />
G1 and G7 refer both refer to aerodynamic drag models based on particular &#8220;standard projectile&#8221; shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferable for flat-based bullets, while G7 is ordinarily a &#8220;better fit&#8221; for longer, boat-tailed bullets.</p>
<p><center><img src="https://accurateshooter.net/Blog/g1g7shape.png" alt="G1 G7 Ballistic coefficients"></center></p>
<p><img border="1" class="alignright" hspace="6" src="https://accurateshooter.net/Blog/blitzx200.jpg"><strong>Drag Models — G7 is better than G1 for Long-Range Bullets</strong><br />
Many ballistics programs still offer only the default G1 drag model. Bryan Litz, author of <a href="https://thescienceofaccuracy.com/store/" target="_blank">Applied Ballistics for Long Range Shooting</a>, believes the G7 standard is preferrable for long-range, low-drag bullets: “Part of the reason there is so much ‘slop’ in advertised BCs is because they&#8217;re referenced to the G1 standard which is very speed sensitive. The G7 standard is more appropriate for long range bullets. Here&#8217;s the results of my testing on two low-drag, long-range boat-tail bullets, so you can see how the G1 and G7 Ballistic coefficients compare:</p>
<p>G1 BCs, averaged between 1500 fps and 3000 fps:<br />
Berger 180 VLD: 0.659 lb/in²<br />
JLK 180: 0.645 lb/in²</p>
<p>The reason the BC for the JLK is less is mostly because the meplat was significantly larger on the particular lot that I tested (0.075″ vs 0.059″; see attached drawings).</p>
<p>For bullets like these, it&#8217;s much better to use the G7 standard. The following BCs are referenced to the G7 standard, and are constant for all speeds.</p>
<p>G7 BCs:<br />
Berger 180 VLD: 0.337 lb/in²<br />
JLK 180: 0.330 lb/in²</p>
<p>Many modern ballistics programs, including the free online <a href="https://www.jbmballistics.com/ballistics/calculators/calculators.shtml" target="_blank">JBM Ballistics Program</a>, are able to use BCs referenced to G7 standards. When available, these BCs are more appropriate for long range bullets, according to Bryan.</p>
<p>[Editor&#8217;s NOTE: BCs are normally reported simply as an 0.XXX number. The lb/in² tag applies to all BCs, but is commonly left off for simplicity.]<br />
<font size="1" color="ffffff">This article is copyright 2023 AccurateShooter.com. No 3rd Party republication of this article is allowed without advance approval and payment of licensing fees.</font></p>
]]></content:encoded>
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		</item>
		<item>
		<title>G1 vs. G7 Ballistic Coefficient Models &#8212; What You Need to Know</title>
		<link>https://bulletin.accurateshooter.com/2023/07/g1-vs-g7-ballistic-coefficient-models-what-you-need-to-know-2/</link>
		<comments>https://bulletin.accurateshooter.com/2023/07/g1-vs-g7-ballistic-coefficient-models-what-you-need-to-know-2/#comments</comments>
		<pubDate>Thu, 13 Jul 2023 05:55:13 +0000</pubDate>
		<dc:creator><![CDATA[Editor]]></dc:creator>
				<category><![CDATA[Bullets, Brass, Ammo]]></category>
		<category><![CDATA[Competition]]></category>
		<category><![CDATA[Tech Tip]]></category>
		<category><![CDATA[Ballistic Coefficient]]></category>
		<category><![CDATA[ballistics]]></category>
		<category><![CDATA[Berger Bullets]]></category>
		<category><![CDATA[Bryan Litz]]></category>
		<category><![CDATA[Bullet Drag]]></category>
		<category><![CDATA[Drag Model]]></category>
		<category><![CDATA[G1]]></category>
		<category><![CDATA[G7]]></category>
		<category><![CDATA[G7 Model]]></category>
		<category><![CDATA[Long-Range]]></category>
		<category><![CDATA[Trajectory]]></category>

		<guid isPermaLink="false">http://bulletin.accurateshooter.com/?p=69172</guid>
		<description><![CDATA[Over the past 12 months, this article was one of the TOP TEN most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. CLICK HERE to watch the video. The better, up-to-date [&#8230;]]]></description>
				<content:encoded><![CDATA[<p><img src="https://accurateshooter.net/pix/gmodel1801op.png" alt="G1 G7 BC drag models"></p>
<p><em>Over the past 12 months, this article was one of the <strong>TOP TEN</strong> most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. <a href="https://youtu.be/gjzs79kDr6E" target="_blank">CLICK HERE</a> to watch the video.</em></p>
<p><img class="alignright" hspace='6' src="https://accurateshooter.net/Blog/g1g7entry.jpg" alt="G1 G7 BC drag models">The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You&#8217;ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn&#8217;t mean you should select a G1 value simply because it is higher.</p>
<p>Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: &#8220;I went on the <a href="https://www.jbmballistics.com/ballistics/calculators/calculators.shtml" target="new">JBM Ballistics</a> website to use the web-based <a href="http://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi" target="new">Trajectory Calculator</a> and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?&#8221;</p>
<blockquote><p><font size="3" face="Tahoma">The simple answer is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.</font></p></blockquote>
<p><b>G1 vs. G7 Ballistic Coefficients &#8212; Which Is Right for You?</b><br />
G1 and G7 refer both refer to aerodynamic drag models based on particular &#8220;standard projectile&#8221; shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferable for flat-based bullets, while G7 is ordinarily a &#8220;better fit&#8221; for longer, boat-tailed bullets.</p>
<p><center><img src="https://accurateshooter.net/Blog/g1g7shape.png" alt="G1 G7 Ballistic coefficients"></center></p>
<p><img border="1" class="alignright" hspace="6" src="http://accurateshooter.net/Blog/blitzx200.jpg"><strong>Drag Models — G7 is better than G1 for Long-Range Bullets</strong><br />
Many ballistics programs still offer only the default G1 drag model. Bryan Litz, author of <a href="http://www.appliedballisticsllc.com/" target="_blank">Applied Ballistics for Long Range Shooting</a>, believes the G7 standard is preferable for long-range, low-drag bullets: “Part of the reason there is so much ‘slop’ in advertised BCs is because they&#8217;re referenced to the G1 standard which is very speed sensitive. The G7 standard is more appropriate for long range bullets. Here&#8217;s the results of my testing on two low-drag, long-range boat-tail bullets, so you can see how the G1 and G7 Ballistic coefficients compare:</p>
<p>G1 BCs, averaged between 1500 fps and 3000 fps:<br />
Berger 180 VLD: 0.659 lb/in²<br />
JLK 180: 0.645 lb/in²</p>
<p>The reason the BC for the JLK is less is mostly because the meplat was significantly larger on the particular lot that I tested (0.075″ vs 0.059″; see attached drawings).</p>
<p>For bullets like these, it&#8217;s much better to use the G7 standard. The following BCs are referenced to the G7 standard, and are constant for all speeds.</p>
<p>G7 BCs:<br />
Berger 180 VLD: 0.337 lb/in²<br />
JLK 180: 0.330 lb/in²</p>
<p>Many modern ballistics programs, including the free online <a href="https://www.jbmballistics.com/ballistics/calculators/calculators.shtml" target="_blank">JBM Ballistics Program</a>, are able to use BCs referenced to G7 standards. When available, these BCs are more appropriate for long range bullets, according to Bryan.</p>
<p>[Editor&#8217;s NOTE: BCs are normally reported simply as an 0.XXX number. The lb/in² tag applies to all BCs, but is commonly left off for simplicity.]</p>
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		<title>G1 vs. G7 Ballistic Coefficient Models &#8212; What You Need to Know</title>
		<link>https://bulletin.accurateshooter.com/2019/09/g1-vs-g7-ballistic-coefficient-models-what-you-need-to-know/</link>
		<comments>https://bulletin.accurateshooter.com/2019/09/g1-vs-g7-ballistic-coefficient-models-what-you-need-to-know/#comments</comments>
		<pubDate>Thu, 05 Sep 2019 11:50:32 +0000</pubDate>
		<dc:creator><![CDATA[Editor]]></dc:creator>
				<category><![CDATA[Bullets, Brass, Ammo]]></category>
		<category><![CDATA[Reloading]]></category>
		<category><![CDATA[Ballistic Coefficient]]></category>
		<category><![CDATA[ballistics]]></category>
		<category><![CDATA[Berger Bullets]]></category>
		<category><![CDATA[Bryan Litz]]></category>
		<category><![CDATA[Bullet Drag]]></category>
		<category><![CDATA[Drag Model]]></category>
		<category><![CDATA[G1]]></category>
		<category><![CDATA[G7]]></category>
		<category><![CDATA[G7 Model]]></category>
		<category><![CDATA[Long-Range]]></category>
		<category><![CDATA[Trajectory]]></category>

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		<description><![CDATA[Over the past 12 months, this article was one of the TOP TEN most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. CLICK HERE to watch the video. The better, up-to-date [&#8230;]]]></description>
				<content:encoded><![CDATA[<p><img src="http://accurateshooter.net/pix/gmodel1801op.png" alt="G1 G7 BC drag models"></p>
<p><em>Over the past 12 months, this article was one of the <strong>TOP TEN</strong> most-read Daily Bulletin features. We&#8217;re reprising it today for those who may have missed it the first time. The above diagram comes from a TiborasurasRex YouTube Video comparing G1 and G7 BC models. <a href="https://youtu.be/gjzs79kDr6E" target="_blank">CLICK HERE</a> to watch the video.</em></p>
<p><img class="alignright" hspace='6' src="http://accurateshooter.net/Blog/g1g7entry.jpg">The better, up-to-date ballistics programs let you select either G1 or G7 Ballistic Coefficient (BC) values when calculating a trajectory. The ballistic coefficient (BC) of a body is a measure of its ability to overcome air resistance in flight. You&#8217;ve probably seen that G7 values are numerically lower than G1 values for the same bullet (typically). But that doesn&#8217;t mean you should select a G1 value simply because it is higher.</p>
<p>Some readers are not quite sure about the difference between G1 and G7 models. One forum member wrote us: &#8220;I went on the <a href="http://www.jbmballistics.com/ballistics/calculators/calculators.shtml" target="new">JBM Ballistics</a> website to use the web-based <a href="http://www.jbmballistics.com/cgi-bin/jbmtraj_simp-5.1.cgi" target="new">Trajectory Calculator</a> and when I got to the part that gives you a choice to choose between G1 and G7 BC, I was stumped. What determines how, or which one to use?&#8221;</p>
<blockquote><p><font size="3" face="Tahoma">The simple answer is the G1 value normally works better for shorter flat-based bullets, while the G7 value should work better for longer, boat-tailed bullets.</font></p></blockquote>
<p><b>G1 vs. G7 Ballistic Coefficients &#8212; Which Is Right for You?</b><br />
G1 and G7 refer both refer to aerodynamic drag models based on particular &#8220;standard projectile&#8221; shapes. The G1 shape looks like a flat-based bullet. The G7 shape is quite different, and better approximates the geometry of a modern long-range bullet. So, when choosing your drag model, G1 is preferrable for flat-based bullets, while G7 is ordinarily a &#8220;better fit&#8221; for longer, boat-tailed bullets.</p>
<p><center><img src="http://accurateshooter.net/Blog/g1g7shape.png" alt="G1 G7 Ballistic coefficients"></center></p>
<p><img border="1" class="alignright" hspace="6" src="http://accurateshooter.net/Blog/blitzx200.jpg"><strong>Drag Models — G7 is better than G1 for Long-Range Bullets</strong><br />
Many ballistics programs still offer only the default G1 drag model. Bryan Litz, author of <a href="http://www.appliedballisticsllc.com/" target="new">Applied Ballistics for Long Range Shooting</a>, believes the G7 standard is preferrable for long-range, low-drag bullets: “Part of the reason there is so much ‘slop’ in advertised BCs is because they&#8217;re referenced to the G1 standard which is very speed sensitive. The G7 standard is more appropriate for long range bullets. Here&#8217;s the results of my testing on two low-drag, long-range boat-tail bullets, so you can see how the G1 and G7 Ballistic coefficients compare:</p>
<p>G1 BCs, averaged between 1500 fps and 3000 fps:<br />
Berger 180 VLD: 0.659 lb/in²<br />
JLK 180: 0.645 lb/in²</p>
<p>The reason the BC for the JLK is less is mostly because the meplat was significantly larger on the particular lot that I tested (0.075″ vs 0.059″; see attached drawings).</p>
<p>For bullets like these, it&#8217;s much better to use the G7 standard. The following BCs are referenced to the G7 standard, and are constant for all speeds.</p>
<p>G7 BCs:<br />
Berger 180 VLD: 0.337 lb/in²<br />
JLK 180: 0.330 lb/in²</p>
<p>Many modern ballistics programs, including the free online <a href="http://www.jbmballistics.com/" target="new">JBM Ballistics Program</a>, are able to use BCs referenced to G7 standards. When available, these BCs are more appropriate for long range bullets, according to Bryan.</p>
<p>[Editor&#8217;s NOTE: BCs are normally reported simply as an 0.XXX number. The lb/in² tag applies to all BCs, but is commonly left off for simplicity.]</p>
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