I have run across where sometimes the bronze guides will actually shrink either from heat cycles or overheated or the quality of the bronze material isn't very good and they will start to slip or move around, not necessarily because of improper machining.

Like what was said before what size is the guide bore? Generally the guide bore is .500 id and the guide od is .502 and if the guide bore is bigger you should be able to find guides that are bigger in od and the guides might have to be polished down to get the proper press fit.

A very good quality bronze guide to use would be C.H.E they can make exactly what you need or you can usually find a guide thats close and make it fit your application. Here is the link for them below.

.https://www.cheprecision.com/html/guides.html