Friend of mine has built a 375 H&H on an FN M98 Mauser. He is using a Sunny Hill bottom metal. Looks to me as if some action machine work will be needed to allow feeding. Can you recommend someone who can do this type of work? Thanks.

375 in a 98 always requires work on the bolt stop, feed ramp and feed rails. I assume you have the longer/wider magazine box that's also necessary. If you don't have the correct mag box, that's where you start. You will have to get one made.

I assume the chamber mouth is correctly beveled. If not you make your task more difficult.

You can do the necessary work with a dremel tool or equivalent. But it does take some care and skill.

First up you have to make the action opening longer, and it has to match the mag box outline. Take as much as you can from the back before cutting into the feed ramp. It is helpful to have a mill to get into the rear corners, otherwise a small carbide burr will do.

Feed ramp has to be recut, it will be shorter but also must be wider.

Then the rails. One side at a time. This is the trickiest part and hard to explain. Starting from the outline of the max box, you have to get a concave rail on each side (from the bottom) and then gradually open the rails until the ctg pops loose at the right time.

Finally the follower might need some work. If third ctg (from the bottom) will feed but first ctg will not feed from the follower, you will need to relieve ridge on follower.

I don't work on other people's firearms so I will leave it to others to offer their services, if you don't want to try it.