Not sure but I think some of the newer actions may have an opening long enough to fit the larger box without any mods to the bottom of the receiver. I have a 116 accutrigger model that has a pretty good size gap from the front of the mag box to the front of the opening at the bottom of the feed ramp. I haven't been able to measure it yet but looks like it just might be long enough to fit a full length cartridge in it.