I have a .750" 16" hanson and love it. Super balanced gun and does 1 moa at 100yds and have shot it out 400yds no problem with 1-4x viper pst. Im about to start my sbr project and was debating between the .625 and .750. The weight savings dont seem like much(3-4oz depending on length), and the .750 is a hair cheaper. But on the other hand is it a waste of weight? Will the .625 do everything the .750 will amd still be lighter? I will be adding saker 7.62 in the future. Any body have any insight? I also have a 14.5" elw bcm upper that has a .625 gas block and a similar profile and have never had any trouble, shoots great and havent noticed any poi difference after long strings of fire but i gavent heard if adding a suppressor has been ok'd by bcm or not?