Decided on building up my next rifle out of a R700 SPS Varmint in .300 WinMag, and fitting it in a Bell & Carlson Tactical Medalist A5 Stock.. However, I notice a lot of you have a 10rd detachable box magazine, but I only find hinged floorplate R700's? Is there a model of the R700 that comes with detachable magazines, or is there a modification thread around here to make them fit?