I bought a 7" tube at a gun show not knowing what it came off of.When I put the barrel nut it came with on my receiver( AR-15) it had a little play in it like it was a little out of speck it wobbled a little on the threads but it did torque down nice to 45 Lbs and the barrel is tight. Does this sound ok or could it be the nut for an AR-10 would that nut be that close or not even fit and torque right.
All the AR10 barrel nuts I’ve messed with were a lot bigger than a AR15 barrel nuts. I’ve seen an AR10 that used the same barrel wrench as a 223 on but the threaded end was bigger. More than likely you have a 223 barrel nut, it may be a junk one.