M1 Carbine loose front sight (again)

Previous post:

https://www.reddit.com/r/M1Rifles/s/McF1z65lvs

Well it was snug. Ran the first 100 rounds through it this afternoon, and it loosed up again. Not nearly as bad, about a 1/16 or so of play to it now. It loosed up in the first couple magazines. I replaced the key with a Fulton armory and reused the pin.

Not sure what else to do now. Could it be the inset for the key has gotten elongated over time? I am about ready to try the loctite method.