I am thinking about getting a Bushmaster Varminter, primarily for prairie dogs and rabbits.

With this, though, I need a scope.  I really like Leupolds and have 2 already for my bolt actions.  I was thinking of getting a VX-III 8.5-25x50 with a varmint reticle.  This is a 30mm tube scope so I will need 30mm rings.  I was wondering if this was an ok scope to use on an AR style rifle, or should I go with a Mark 4 8.5-25x50 mil-dot?  

what do yall think? is the magnification over kill, I want to actually be able to see the prairie dogs out past 300yds?  Also, what is the best way to mount the scope?  The rifle comes with the mini risers, so if I just go with rings that mount to the picatinny rail would I need low or medium, doubt I would need high.  Or should I go with an adapter from picatinny to weaver and just get standard rings?  Sorry if this has been asked before, I tried searching to no avail.

Thank you.

btt

whatever scope you want to use would work fine
with the mount/rings if there is enough eye relief when shouldered i would probably use regular rings, though you migh need either high or ultra-high rings and i would ditch the risers


if there isnt enough eye relief then i would go with either a larue spr,eer mount or med rings on a riser/rail extender

Keep it as simple as possible...the scope and the right rings should be all you need, unless you want to move the scope forward some.   On a standard flat top with no extension, the eye of the scope will almost certainly be farther back than *some* folks like it, and the longer the scope, the furhter back the eye is, obviously.  At 14 1/2", that Leupold is pretty long, so you might be a problem for you.  

The Armalite on piece mount and the LaRue mounts will move the scope forward...the RRA does, but only about 1/2", which is next to nothing, really.  

The LaRue is a very nice mount, but it's $200 or so, a little more if you get the EER version...and if you're stretching your budget with that scope, you might consider another solution, like the Yankee Hill Rail Extenders.  They also act as a riser, so you could probably get away with low rings if you're gonna go that route.  ARMS makes rail extension too, and I've seen several on the EE lately for pretty cheap.  

It sounds like you'll have a *very* nice rig when you're done, and I'm sure marmots everywhere will fear you.  

hrm I didn't think about the scope being too long, I might have to rethink some things.  Thanks for y'all's help