Roy 44 is right on.
You can use the modern oil mix at 40:1 or 50:1.
I have some of the old Rem's and Mac's and use anywhere from 32:1 to 50:1 with no problems.
Keep a heads up on those old Remington's and if you see excessive smoke, sometimes they will begin to burn bar oil due to a check valve leaking that pressurizes the oil tank.
Here is a link to a chainsaw/logger place that enjoys hearing about those old saws, may find some parts and manuals and lots of tips from some old chainsaw geezers. scroll down until you see chainsaws.
It's easy to post up a picture of your saw here also.
https://www.arboristsite.com/community/