Prairieschooner,

That is the 'old way' of mounting a reel which is one of the reasons they developed screw on styles. I would suggest just living with it, and as you indicated, check it often. I doubt that milling out the ring would do any good, it would just weaken it and it would still slip, maybe even easier. But then, maybe someone has a solution to the problem. With mine, I just 'live with it'.

Larry ---sagefisher---