I just bought a SS Model 70 in 300 Ultra Magnum. I might keep it as is if it shoots good but my main objective is to use the action to build a big 338. The problem is that Model 70s are not usually well endowed when it comes to magazine boxes. I don't want a single shot so my question is, what is the largest 338 magnum that I get fit into that action/magazine box for long range shooting (i.e. I want to shoot SMKs or some other high BC bullets). I probably would prefer a 338 RUM or maybe a 338 Edge but am worried that the magazine box is going to be too short to seat the bullets to the proper lengths if the cases are too long. Has anyone built a 338 RUM, Edge, or 338/300 RUM or the like in a Magnum length Model 70 Action and been able to seat the bullets out to the proper length? Does the 300 Ultra Model 70 have a longer magazine box than the standard magnum length Model 70s and if not, can this action accommodate a magazine box long enough to be able to seat SMK or VLD bullets to just off the lands? If 338 RUM or Edge won't work, would anyone like to add their 2 cents on building a 330 Dakota or a .338-.375 Campfire (built on Ruger's new .375 Ruger)? Something else? I really like Model 70s but the short magazine boxes are the pits. I hope Winchester sees the light with their new rifles and adds a little more length to their magazine boxes.