Bramble,

I agree with you concerning taking metal out of the action that it has to have some kind of impact on the strength. But I also believe like you that the amount taken out to build a .404 Jeffery would not be of signifance to make the action unsafe. Like you stated, this has been done for decades by gunsmith's. I do believe that the work needs to be done by someone who knows what he is doing or you could end up with an unsafe action.

Since I only will use factory loads and the .404 Jeffery is such an old caliber I do not believe that ammo manufactures will ever load this cartridge to hot. I imagine it will be treated the same as the 7x57, but these are only myu opinions.