It could be done, yes, provided you're in compliance with state laws regarding calibre for the type of game you're taking, and in compliance with magazine capacity laws which may be in effect for hunting.
Yes, Ruger made them
50-200
Ruger.
Ruger's web site has extensive sn data.
Depends on what caused the jam.
Check the receiver and barrel
75-300
Depends on the store.
it is worth ..............$$$$
50-200
Not recommended.
50-225 usd