I usually load Speer 125 gr TNTs, Sierria 165gr SPBTs, Nosler 180gr Ballistic Tips and Partitions. I can not remember the powders I am pushing them with and I can not get to my reloading bench right now. Will try and give you that information tomorrow. The Handi 30-06 is my favorite gun. I carry it year round for everything from Moose and Caribou to Wolves and Coyotes. I really don't want to run across a Big Bear with it, but if it happens it will do the job if I do my part I am sure. Lynx and Foxes are the only things I don't like shooting with it. A little too much gun for them. Love to shoot Red Squirrels with it. The result is totally awesome.
I have shot wolves out to 700 yards with it, but try and limit my shots to not more than 500 yards. The Caribou in my avitar was shot with my Handi 30-06, using a 180gr Nosler Partition, at 250 yards.
As for keeping that barrel, I would. It is the most versatile cartridge made. That barrel deserves it's own receiver. It can be used for every kind of big game in North America, even the Big Bears of Alaska if you do your part. You can load cartridges with bullets from 95gr to 250gr. The only one I have had bad performance from was the Speer 100gr Plinker. You have to hold the velocity down with that bullet, or it comes apart in flight. It is so short and fat it's like shooting a pistol bullet. I personally have not loaded the 95gr bullets, I think they would be a repeat of the 100gr loads. I have loaded the Barnes 250gr bullets. They pack a wallop, my wife killed a charging Grizzly with them.