Missed Curl's post in my first pass, all good advice. I can only add that there are a number of 440gr thin-jacketed soft-points around that will suit that chambering, although they are probably better with a 'nitro for black' load. In Australia, Woodleigh and Bertram offer 440-grainers.

The 550gr pills mentioned above are too heavy by far.

As mentioned above, read Wrightie's book cover-to-cover when it arrives, to avoid damaging a golden oldie or risking personal injury.