Excellent point. I honestly can't recall if I considered that or not.

I just looked at the gun again and the 6" barrel.

The 6" may have a very light scuff around it where the crane lip would hit. I can't see any marks on the on the 4" or the crane lip, but it was a long time ago and the gun has been fired and cleaned many times since. Still accurate and butter smooth.

So now I'm wondering. I do recall being concerned about deforming the crane bore on the frame before I removed the barrel and I know I filled the bore for support.

The question I can't recall is whether or not I inserted the actual crane and got lucky both times, removing and installing barrels. There is some clearance between the assembled barrel at the flat and crane lip. Enough to clear? I don't know but it doesn't look like it. Or perhaps I put a rod of the proper diameter in the bore and that old post is wrong.

Anyway it's a good point to keep in mind.

These are great old guns, they're getting somewhat more scarce and valuable and I don't think I'd mess with one now. If I should ever sell it, unlikely, I'd just tell the buyer the history and include the original barrel with advice to have an expert restore it if they so choose.