Saturday, April 11, 2020

BCM stuck barrel lock nut : or : patience when it matters getting stuck things unstuck

BCM makes some great stuff however their AR uppers can be somewhat difficult to work on from time to time. Usually at the top of the list for difficulty is front sight taper pins and stuck barrel lock nuts. I've run into both and had to get help with the front sight pins. The lock nut is our focus here for this short post. I had mounted the upper in the action block in an attempt to remove the barrel and it simply would....not....budge.... I broke 2 teeth off the nut in fact in my attempt. Before I got super carried away I realized I had no need to get the barrel out that night, it was getting late and I had time so I put some Kroil oil around the base of the lock nut on the receiver side of things and set it next to the wall by the wood stove over night.

The next day I tried again, I readied my mental state of mind for physical combat with a lock nut that simply would not budge and chucked it up in the vise, put the action wrench on it and before I even started thinking about grunting in effort it came loose long before I thought it would. You see heat and oil and time allowed the surfaces to expand and contract and allow the lube to flow into all the areas and make our life a little easier. I've seen stories of people using LONG cheater bars and flame heat to get nuts to loosen up however it costs nothing to put some oil on a stuck nut and set it aside overnight and work on a different project.

One of my favorite methods I've seen for stuck bolts (even broken bolts) or nuts is welding a nut over the top of it and using a air power impact wrench to get it loose. The heat and vibration do wonders in getting it loose. If you break off the nut simply weld another back on and try again.....it will come loose eventually.....the more you know.

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