OP I have a 260 that was exactly the same as your 243

4.40 short action DBM center feed with the axis style mag.

I went with a DBM inlet Choate tactical, it does not use the axis style mags so that is some parts you'd have to get but you can get them from savage and there are a few other option.
Pretty much any other stock I know of will require some change of the mag setup.