it would be wayyyy simpler to build a 358 on an Ar10 type platform.... modern hunter, bcl102 and stag-10. Reason being that it is much simpler to manufacture an AR10 type barrel compared to manufacturing an M14/M1A barrel. I quested for years to have an M14 barrel made in .338 federal ...... got so close with mcgowan I could almost taste it and then they tossed the project. After the effort I put in to make that happen and the embarassment due to mcgowans let down...... I gave up on getting custom calibers done for the m14 and find I'm not having those issues with building my stag-10's. I've already been assured by several sources that .338 federal and 7mm-08 will be a walk in the park to aquire.