Twist rate?

[couture]

Is the twist rate of an AR stamped on the barrel? If not how do I find out what it is?

[Albroswift]

If it is not stamped on the barrel (which it usually is) you can put a cleaning rod in with enough cleaning pad so tight fit, ark it with a sharpie, then measure how far it needs to move to make 1 full rotation. Or 1/2 rotation and double, etc. If it moves 5" to make 1/2 rotation or 10" to make full rotation you have 1:10. 

[JMJ]

2 hours ago, Albroswift said:

If it is not stamped on the barrel (which it usually is) you can put a cleaning rod in with enough cleaning pad so tight fit, ark it with a sharpie, then measure how far it needs to move to make 1 full rotation. Or 1/2 rotation and double, etc. If it moves 5" to make 1/2 rotation or 10" to make full rotation you have 1:10. 

Thanks for posting this! That’s a whole lot easier than “slugging” a barrel to determine the twist rate.