And if so can it be done safely and what should I look for? A commercial FN I should add.

If you are talking about the basic non-magnum action then yes it would have to be opened up to handle the 416Rem. The FN would not be my choice. If you want a 416 go with the 416 Taylor. If you want the 416Rem go with a different action.

I see no reason not to open up an FN action to a 416 Remington as they were once produced in 375 and 404 and I never heard of a problem with them in those calibers...Open it up in the rear as much as possible...Same as a Mauser M-98....My 416 is a Mauser 98...

I machine trigger guards for the 416 Rem for the Mauser.

I always open up 30-06 or short magnum actions rather than using their 375 action.

First the rear of the box is moved as far to the rear as possible.
The thickness of the rear wall is kept to .075".
The bolt stop needs to have about .040" removed from it so the bolt will pick up from the magazine.
Then the feed ramp and rails are remachined to match the guard, and hand worked over to feed properly.
The inside length of my 416 guards is 3.700", this will leave .080" more metal that the FN 375 recievers had in the feed ramp area because we have moved the rear wall back.

Jim Wisner
Custom Metalsmith
jwisner@quik

I just purchased a 416 on a FN action via guns amereica, we'll see how it was done in a few days and I'll report back with photos from my inspection.

Jim,
Do your triggerguards have the floorplate release in the bow ala 1909 or Mark X guards?