The Firing Line Forums - View Single Post - ar-15 barrels.

Bartholomew Roberts · January 17, 2010, 09:08 AM

On an 18" barrel, I would go with a rifle length gas system. My personal chart is:

10.5"-14.5" = carbine gas
14.5-16.5" = midlength gas
17"* and up - rifle gas

*The 17" is only if MSTN builds it; otherwise 18"

January 17, 2010, 09:08 AM	#7
Bartholomew Roberts member Join Date: June 12, 2000 Location: Texas and Oklahoma area Posts: 8,462	On an 18" barrel, I would go with a rifle length gas system. My personal chart is: 10.5"-14.5" = carbine gas 14.5-16.5" = midlength gas 17"* and up - rifle gas *The 17" is only if MSTN builds it; otherwise 18"