03-19-2012, 09:42 PM
The main gas block diameters are:
.625" This is what was on the M16A1 and early model military guns with lightweight barrels. Not common on a lot of modern guns, but seeing a resurgence in new lightweight barrels chambered in 5.56 NATO.
.750" This is what became the standard with the M16A2 and its heavy fore end, and is the most popular 5.56 barrel gas block diameter.
.875" This is used on some medium-heavy contour barrels on target guns.
.936" This is used on heavy barrels meant for target shooting.
.625" This is what was on the M16A1 and early model military guns with lightweight barrels. Not common on a lot of modern guns, but seeing a resurgence in new lightweight barrels chambered in 5.56 NATO.
.750" This is what became the standard with the M16A2 and its heavy fore end, and is the most popular 5.56 barrel gas block diameter.
.875" This is used on some medium-heavy contour barrels on target guns.
.936" This is used on heavy barrels meant for target shooting.