Sorry for the dumb question, but I am fairly new to having a custom rifle built. I can get a 7mm-mag Rem. action for a resonable price, and was wondering how much work would have to be done to the action, to convert it to 338RUM.
The Rem 700 long action will handle any round from the '06 to the RUM case.
Since you already are looking at the 7mm Rem Mag chambering, the bolt face is already a magnum bolt face, same as the RUM. Only thing I have seen is that some bolt heads need a bit more chamfer on the inside of the bolt nose to work well with the large diameter rebated rim design of the RUM case.
Other then that, you can order in a Rem RUM box mag from Brownells which is a drop in fit to the receiver.
The feed rails may need some slight opening. I have built on Rem 700 standard magnum receivers that did not need anything but most need a bit taken off the feed lips, just enough for the big RUM case to fit between them is perfect.
If you want to seat your bullets longer then standard then a Wyatts mag box is a good choice but it is not a nessesity with the 338 RUM chambering.
Other then that the 7mm Rem Mag receiver will work perfectly.
Allen Precision Shooting
Home of the Allen Magnum, Allen Xpress and Allen Tactical Wildcats and the Painkiller Muzzle brakes.
R.R., your smith would also need to make the feed ramp wider and deeper to make the rounds feed properly. When you put a 7mm Rem mag action side by side with a RUM action you can easily see the difference in the feed ramp.--RHB--