Rem 700 .308 conversion

[skookum]

M y cousin recently bought a Rem 700 SPS in .308 with 20'' barrel, He thought it was a neat toy i guess but had a change of heart once he figured out that the rifle is a little impractical for hunting. Now he wants to convert it over to a 300 wsm. What all would he have to do to make this conversion and would it be worth going through or would he be better off just selling it and buying another rifle all together. Keep in mind that He is looking for the most cost effective option. i appreciate the input.