One of my long time hunting buddies had a .340 wby restocked and converted to a .338-378 when the concept first became popular, maybe 30 years ago. He used it exclusively on our northern moose and grizzly hunts. At that time there was no factory brass and very little loading data so it took a while to do load development. He settled on 250 grain Noslers doing about 3000 fps out of a 26 inch barrel. (no muzzle brake) That rifle accounted for many large moose at long range and a considerable number of grizzly, including one that was rapidly approaching me at a time when I couldn't get at my rifle. It is a very effective hunting weapon. On the downside, you don't carry it far unless you are strong and in great shape. We hunt the swamp and muskeg country between the Alaska Highway and the Yukon border - and we do it on mud rigged four wheelers so hauling heavy and awkward rifles isn't a problem. These rifles aren't handy so fast shots and bringing them into battery is a process. Then there is recoil. When my friend got into his '70's he retired this rifle and now uses a 300 ultramag. You can suffer serious whiplash just sighting in his old rifle. As for the scope bases and rings, once he got a set-up he liked he epoxied the bases down and the rings to the bases and has had no problems. I had been doing that since the '70's when my benchrest buddies showed me how. A little bit of heat from a finely adjusted torch and they come apart if necessary but it removes one of the variables on the way to consistency.