Have been using the older gen Savage/Stevens rifles for a very long time. They can be set up to run superbly .... in some applications. I am not a fan of the new gen actions and the cost cutting measures Corp Savage has done. They can also have some issues with ejection... very hit and miss.
Run as a single shot F Class rifle, I really like what it offers. For a mag fed rifle, I only use it for practise.
Since you want to run a chassis and the MDT LSS is your choice, I would strongly recommend the Rem 783.. specifically the newer oversized bolt knob variants. They run superbly with AICS mags. All the positives of the Savage, none of the negatives and a bunch of extras that make this action my fave for a factory donor.
If I can help with the chassis, let me know as I am offering discounts now.
With a match prefit barrel, they will run with the custom rifles ....
Rem 700 is well understood in the good and bad... again, not a fan of the actions over the last 5 to 8 yrs. If you can get some real old ones, they can work very nicely. nothing comes close wrt to options and parts. if the action has been manf decently, they run well... if not, money to fix and then you loose the point of a budget build.
Howas are very nice actions. Definitely underrated but Legacy Sports is working hard to change that. A very solid action, not much aftermarket but that might change given the corp support. If just looking at the pure action, I would choose the Howa over the Rem 700
Jerry