Join Date: Apr 2018
Location: Disneyland Anaheim CA
Model: Aspencade 1500
Isn't that a wire type C clip?
If so replacing it with a real snap ring or better yet a spiral lock will probably hold better in your worn grove. There are also push in retaining rings with teeth that grip the bore and don't even require a groove.
As mentioned above the real fix is to clean up the groove in a mill or lathe. Round profile for a wire C clip, square profile for a snap ring or spiral lock.
Go to McMaster Carr and search "Internal Retaining Rings".