30 Cal Rifling Twist Rate

Paladinpainter · 04-05-2015, 08:53 PM

Sieger,
I'm going to jump in here and question the notion that an over-spun bullet has a different terminal effect than a normally spun bullet. If the target is 10" thick, a bullet leaving a 1 in 9.84" twist barrel, will rotate about one time before it exits. ( Not tumbling). A bullet leaving a 1 in 20" twist barrel will rotate about half that amount. In either case, and with out testing, I have a hard time believing that one half a rotation of the projectile is significant in any way. Now if the projectile upsets on entry, that might be different. But we're still talking about 1 rotation in each 10 inches of travel.
Regards,
John

04-05-2015, 08:53 PM	#11
Paladinpainter User Join Date: Nov 2009 Location: Vermont Posts: 64 Thanks: 14 Thanked 45 Times in 15 Posts	Sieger, I'm going to jump in here and question the notion that an over-spun bullet has a different terminal effect than a normally spun bullet. If the target is 10" thick, a bullet leaving a 1 in 9.84" twist barrel, will rotate about one time before it exits. ( Not tumbling). A bullet leaving a 1 in 20" twist barrel will rotate about half that amount. In either case, and with out testing, I have a hard time believing that one half a rotation of the projectile is significant in any way. Now if the projectile upsets on entry, that might be different. But we're still talking about 1 rotation in each 10 inches of travel. Regards, John