Before you do anything, shoot the rifles and see where you stand. Remember, when hunting you tend not to notice recoil or noise. Shooting off the bench is a whole different story.

I would try (and I have) a PAST shoulder recoil pad for shooting off the bench. That surprisingly helps a lot.

If you can shoot well off the bench with a cheap PAST shoulder pad, the rifle(s) probably don't need any work.

For 375, 9.3 X 74 and even 416, I personally am not bothered by either of them even off the bench sans pad. By the way, the 375 and 9.3 (366 caliber) are pretty close in their numbers.

If you need to reduce recoil after trying these simple solutions, remember three things: (1) they are your rifles, and you can do to them whatever you desire to make yourself comfortable with shooting; (2) if recoil is an issue, you won't be accurate with the rifle as with a smaller caliber (3) anything you do to the rifle in terms of recoil reduction almost always lowers the resale value.

The first modification should probably be the recoil pad. Most stock rifles have pretty crappy recoil pads. There are many great pads out there, with newer ones coming out all of the time. Unless you are dealing with something like an expensive double rifle or a high level bolt gun, replacing a recoil pad is resale neutral. I think Pachymar came out with their latest and greatest recently.

For a 375 or 9.3 X 74, that just might do the trick. A word of advice here - keep the old pads! If you find your new pad hurts the value, you can always put the old one back on.

Again, try it at the range with and without the PACT shoulder pad.

If it is still an issue, then there are alternatives like mercury recoil reducers. They work, but they also add weight to the butt and change the balance of the rifle. That works for some people. But I am one of those who like a nice balance.

And if you feel the need to use one in the 375, think long and hard about putting one into a double rifle. I would imagine that a 9.3 X 74 with a mercury recoil reducer would be an outcaste....

Know also that mercury recoil reducers don't get you points on resale, especially with calibers at the lower level of the big bores. In a 500 Jeffery or 505 Gibbs, there may be some forgiveness (the purists would still cry blasphemy).

If you are having a custom rifle built, the recoil reducer decision should probably be made before the rifle is built for balance and weight purposes.

Just my 2 cents.