"...indent the area in front of the dovetail slot. This
can best be done by using a large steel drift, placing the drift in the
location shown in figure 41, and rapping the drift with a hammer.
Undertake this operation with extreme caution. A blow only hard
enough to cause a flow of metal into the dovetail slot is necessary."
Then stake it. Man, I don't feel good about taking a hammer and drift to a USGI receiver. I have an Auto Ordnance repro with the same problem, so I could practice on something just as expensive but replaceable.