That rifle looks real familiar!!
I have one just like it
, except mine has the full length 10ga forend. Let us know how it shoots, I'm betting it likes the 180gr Hornady SS-PB with about 28gr of AA1680 and a firm roll crimp.
Beware of the noise from that brake. I am contemplating sending mine back to David for an extension without the holes. I just can't imagine shooting it without hearing protection while hunting. It makes my ears hurt with plugs in and muffs on.
Thanks, Dinny