I purchased a used Krieger 223 barrel to build an upper. I am looking for a gas block and the size is .750. My question is if anyone can tell me what these two notches are in the bottom of the barrel. I assume they have something to do with the gas block but I haven't been able to find a gas block that isn't either a clamp on, set screw on the bottom or a pin style.
Any help would be appreciated.
Any help would be appreciated.
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