
We build a lot of rifles here, and we gauge each gas block ID (barrel bore and gas tube bore) within the specifications outlined on the TDP.
It is amazing (and absolutely frustrating) how many gas blocks we have had to scrap or warranty. So frustrating that we needed to build our own that was machined and honed within the very specific requirements of the US Mil-Spec FSB.
We have ramped up manufacturing and are now offering them to our BCM distributers.
We have the 750 ready now, and should have the 625 ready next month.
http://www.bravocompanyusa.com/BCM-Low-Profile-Gas-Block-p/bcm-lgb-.750.htm