HillBilly - Brett has probably done a couple of hundred of them through the shop, and I have worked on maybe 3 or 4.
Is there something you are building the rifle for? Like a specific purpose? Scout Rifle perhaps?
The reason I ask is, traditionally, rifles shoot better long range if they don't have a magazine at all. Benchrest actions, for example, are all solid bottom, single feed style.
If you are really building from the ground up, and you want to get something factory, you should check out the Accuracy International AICS System