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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Sierra 6.5mm 130 grain TGK Twist Rate.
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<blockquote data-quote="kiwikid" data-source="post: 1721946" data-attributes="member: 56094"><p>Hi Guys and Gals,</p><p>Sierra suggest that their new 130 gr TGK requires a 1:8" twist barrel but when I load the data into the JBM Calculator it gives me a stability reading of 1.690 as seen below.</p><p>I have two questions please,</p><p>1. Have I done something wrong with the info I have entered into the calculator?</p><p>2. Has anyone tried these in a 1:9" twist barrel?</p><p></p><p>Thank you for your time and help.</p><p>kiwikid. </p><p></p><p>Stability</p><p>Input Data</p><p>Caliber: 0.264 in Bullet Weight: 130.0 gr</p><p>Bullet Length: 1.380 in Plastic Tip Length: 0.210 in</p><p>Muzzle Velocity: 2800.0 ft/s Barrel Twist: 9.0 in</p><p>Temperature: 59.0 °F Pressure: 29.92 in Hg</p><p>Output Data</p><p>Stability: 1.690</p><p>29-Sep-19 22:26, <a href="https://www.jbmballistics.com/" target="_blank">JBM</a>/<a href="https://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi" target="_blank">jbmstab-5.1.cgi</a></p></blockquote><p></p>
[QUOTE="kiwikid, post: 1721946, member: 56094"] Hi Guys and Gals, Sierra suggest that their new 130 gr TGK requires a 1:8" twist barrel but when I load the data into the JBM Calculator it gives me a stability reading of 1.690 as seen below. I have two questions please, 1. Have I done something wrong with the info I have entered into the calculator? 2. Has anyone tried these in a 1:9" twist barrel? Thank you for your time and help. kiwikid. Stability Input Data Caliber: 0.264 in Bullet Weight: 130.0 gr Bullet Length: 1.380 in Plastic Tip Length: 0.210 in Muzzle Velocity: 2800.0 ft/s Barrel Twist: 9.0 in Temperature: 59.0 °F Pressure: 29.92 in Hg Output Data Stability: 1.690 29-Sep-19 22:26, [URL='https://www.jbmballistics.com/']JBM[/URL]/[URL='https://www.jbmballistics.com/cgi-bin/jbmstab-5.1.cgi']jbmstab-5.1.cgi[/URL] [/QUOTE]
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Rifles, Reloading, Optics, Equipment
Rifles, Bullets, Barrels & Ballistics
Sierra 6.5mm 130 grain TGK Twist Rate.
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