I have an ARC Mausingfield that takes Savage small shank barrels. Unlike the Win M70 pre-64 and Classic actions, this doesn't have an extractor slot cut into the barrel. Why does this work in this rifle but the M70s have to have extractor relief? Could a M70 barrel be made with the same breech as a Savage barrel and work? Is it the specific design of the Mausingfield's claw extractor... and could a revised M70 extractor along those lines allow for eliminating the extractor cut?