Im going to likley use one hole in the nut for a pin type tool . I will be able to spin the tool 360 degrees so I should be able to get away with a single hole . I might o two just in case on strips out or what ever .
I also had a idea for a barrel like wrench with a dowel pin protruding that clamped on the the nut like it would on a a barrel but have the advantage of a pin in a hole in the nut
I can mill a slot just as easy how ever .
I could likely set head space an pinthe nut to the barrel an just use a barrel wrench also . once the head space is set its not likely to need to be readjusted if the barrel is R&R as long as the torgue specs are repeated .
as mentioned before not all barrels will have nut some will have a shoulder to tighten up an just like a bolt action .
I need to get the Z mount figured out an the gas tube an other things I want to test . Im pretty bussy with summer stuff right now .