Re: Upgrade...or new rifle?
If you want to keep your cost down,buy a Hogue full bedding block stock( $200 ),drop in your chambered barrel action and start shooting. Might have to take a dremel tool to free float the barrel, only 5 minutes of work. Have a gunsmith tune the existing trigger( should not cost much). The most improvement in accuracy however will come from a custom barrel, and you will need to decide if it is worth it after you shoot the rifle after the previous improvements are made. Like ICANHITHIMMAN stated, you will not get out what you have in your existing rifle, so just build on what you have. There is no guarantee that if you buy the Sendero for more money that it will shoot any better than what you have now, and you would have to make improvements on the Sendero also. Once you go thru this process,I see a custom build in your future.