New struts are available on the site here. The 260 is the same as the 270 but water ballast vs full keel and internal aux motor vs outboard.
Hunter 260 mast struts, pair
shop.hunterowners.com
If the strut is not too badly damaged and you have all the parts you could take the damaged one to a local welder that is able to weld stainless and see what they would charge you to repair your existing.
I had this type of repair when our 260 was new and being picked up from the dealer. It’s been 9 years and I’m not sure I could tell which was the one repaired.
You could also have one made locally from the factory drawing here: