View Full Version : What makes this lightweight?

03-02-2012, 12:52 PM
What makes this barrel lightweight and can anyone tell me what the (.625FSB) means?



03-02-2012, 1:23 PM
FSB is Front Sight Base (Gas Block). The .625 is smaller and lighter than the heavier .750
It will also get hotter quicker and cool off much faster than a .750 (especially if it is a pencil barrel).

For most it all boils down to personal preference. Though there has been many a voice that says the Light Weight barrels will give less accuracy under heavy use when they get hot. I've never seen this first hand myself but then again, I'm not in a war zone or firing more than 10 rounds in any given moment.

03-02-2012, 1:59 PM
.625 (inches) is the diameter of the barrel at the spot where the FSB or gas block resides.

03-02-2012, 2:56 PM
The lightweight barrels can torque a little bit if you put on a tight sling. The heavier (A2 HBAR) barrels won't bend even if you get tight into a sling.