http://defensereview.disqus.com/NoneenThu, 30 Jan 2020 15:01:43 -0000http://www.defensereview.com/why-isnt-our-military-going-6mm-by-david-crane/#comment-4777363602<p>A counterproposal: The 6mmAR is the Grendel case necked down to accept .243 bullets. When I run the numbers on AMax-shaped bullets of weights 80..90 grains fired from a 6mmAR cartridge and an 18.5" barrel, 87 grains keeps rising to the top as the sweet spot between muzzle velocity (lighter bullets start out going faster) and ballistic coefficient (heavier bullets of a given shape retain their velocity longer).</p><p>Velocity at a given distance and bullet composition determines degree of fragmentation, and degree of fragmentation times bullet mass determines permanent wound cavity volume, which Fackler identified as the dominant factor (besides shot placement) of terminal effectiveness.</p><p>The 87gr's terminal effect looks very good under this model, and represents a local maximum, producing a larger permanent wound cavity at longer ranges than either 85gr or 90gr, and providing some fragmentation out to about 570 yards (the distance at which its velocity drops below 1900 feet/sec).</p>Ttk CiarThu, 30 Jan 2020 15:01:43 -0000http://www.defensereview.com/why-isnt-our-military-going-6mm-by-david-crane/#comment-121544017<p>Interesting, sounds like the 6x41ARP<br>95gr SMK, BC of .480 2750fps from a 18" barrel, sounds perfect for a SAM-R in Afghan</p>HarrisonFri, 31 Dec 2010 03:33:58 -0000