I've personally seen 2 older rifles get much worse after free floating the barrel. I think a lot of the old designs tolerated/relied on barrel contact to create a solid action/barrel/stock mount. The action inlets are always super rough and ill fitting, and once you remove the barrel channel contact, it exposes this weakness, and bedding/pillars are needed to correct it. I know you haven't clearanced this one, but the moral of the story is the same.
Also with regards to heat, I don't think these older barrels ever went through stress relieving like modern barrels do, and the profiles tend to be EXTRA thin compared to what anyone would make today. So I think managing heat is paramount with these old guns, literally 1 shot every 5-10 mins to avoid heat effects.