The best is up to you to decide. Leupold Mark 4 rings
are some of the very best. Nightforce only offers 30mm rings because they only make 30mm scopes
. For hunting guns I prefer two piece bases because there's more room to load from the top, unless you have a detachable magazine; then it doesn't matter. For tactical
guns the one piece may be the way to go. You might be able to get away with mediums with a skinny barrel, but it will be very close and you may want the extra height the high rings offer. You'll have to try them to see if they fit. If you have a heavy barrel you will
need high rings. Consider the excellent 65 inch pound torque wrench
, also. The LR bases mean "Long Range", and have a built in 20 moa angle for long range shooting.