You can get a bolt on clip guide for the 700 or you can have a smith mill a slot. The caveat with that is that you need a long action to have one of the bolt on guides added. Although with somthing like a .223, you might be able to use a bolt on guide with a short action.
With the milled slot, If you're using it for something like a .308. they have to sometimes make a relief on the front receiver ring so that the tip of the bullets can make it down into the magazine.
I know Champion's Choice carries them, but if you call
Larry Racine in North Swansey NH I bet he has one.
B