For a non DG rifle I wouldnt be as concerned about the extractors although I do agree the rimless case is more likely to cause malfunction , on non DG the consequences of a failed extraction probaly wouldnt be as dire . Since I wouldnt be expecting to use it on DG I would not be against having double 30-06 at all . Both calibers (30-06 & 45-70 ) have their advantages , only solution is to get one of each .