Lol ur port is not 0.75". That measurement is the thickness of the barrel where the gas block mounts. It ab be .625, .750 and I belive a bull barrel is .925 Unless you have the proper hardware or are willing to have a gunsmith do some custom work on it, the gas port is already drilled by the barrel maker. Gas ports are not a stat you should really worry about when assembling an AR.
Assumption is the mother of all ****ups.
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