Mine is 2" Id. I use split bushings turned and bored from 6061 for Remingtons.
I prefer working on Winchester's, FN SPRs and Howas. The bushings aren't so great with them. But, they seem more rigid, so perhaps less of an issue.
My phone's all jacked up. Hence the double post. This forum doesn't seem to have a button for deleting a post. This always happens when it's charging on an inverter. The chargers rectifier doesn't like the squarewave ac source.