i hvae talked to hart rifles and they tell me that they will need opened.it only takes a little work and i was told if they chamber for you there is no charge for this carol
.. On my Winchester WSM the feed rails are not big enough to feed the WSM cartridges thru.. But it's set up as a single shot so it doesn't really matter.. If I try to lay a cartridge in too far back in the port the rails tend to "grab" the brass.. I think the amount the rails need to be opened is pretty small and would not amount to much of a difference in the action strength.. .. On the negative side, and this is based on theory, I think if you do this modification the action probably will not work with "standard" mag cases anymore.. d:^) JiNC