Theoretically the 50mm will allow extra light into the scope to produce a better image. Does it really work that way in the real world, that's a matter to debate. Rings, depends on what type of bases you use. The cheapest would probably be Weaver style rings and bases, some like them, some do not. Scope for a total budget of around $200 that does kind of limit your options. I would suggest Nikon Prostaff, Bushnell Elite 3200, Nikon Buckmaster I have also heard some good reviews on the new Vortex scopes from Federal or ATK whatever name they're going by. Have not seen what they are priced at though yet.