I use the 173grain H mantel copper covered hollow point (I brought a supply back from Germany for my 7x57R) in my 7x65R Drilling and it works very much like the partition and A- frame. I have 50 years' experience with it, and it kills very well, without destroying too much meat, even on a small animal like Roe deer. I had good luck with Brenneke slugs, but modern slugs might be better, I haven't tried them. The 7x65R is adequate for Moose, with any of the three bullets and even more so for black bear and Black tail. My favorite drilling has 60cm barrels and 60cm barrels on the O/U are my favorite too. I recommend that length and if you don't like them, you can cut them off again.
Mike