I recommend clients who want Brown Bear to use .300 Magnums.They are flat shooting and have the desired muzzle energy to take down these bruins usually with one shoot, but it sometimes takes more. Depending on bullet placement and distance. .338 Magnums are good too, but a lot of hunters who are not from here have trouble with judging distances. The .338 Magnums have heavier lead and will drop more over long distances. It's big country, and judging distances is part of our job, but clients need to know how to compensate when the time comes. The .300 Magnums are a little more forgiving if your shot is not quite perfect and has much less drop over distances.
A gunsmith friend of mine along with myself, found a B-25 Bomber that still had it's 50 caliber machine gun barrel, that was headed for the scrap pile. We took that barrel, turned about 3/4 of an inch of steel off of it, mounted the barrel to a 1915 Enfield action, which has a three point locking bolt.
We fitted it on a nice stock and began testing rounds. Barnes had made my bullets for me. They were 600 grain lead bullets, with a monolith tip, which meant it would mushroom about halfway back and then stop mushrooming, thereby obtaining optimum width. I purchased brass from Bell Labs now out of California. They specialized in old African calibers. I had to buy .577 Nitro express casings and neck them down to my .505 Gibbs. RCBS made my reloading dies for me, and did a wonderful job. This whole business of "Big Gun" building had become quite the collaborative effort. Now came the fun part,TEST FIRING.
My first few tests used improved military rifle powders, the most up to date. I found this powder to be way too "hot" for the lead. I discussed this problem with the fellow guide community and Cecil Rhoades Dippenhour had the answer. Cecil owned Zingali Safaris out of Malawi Africa, they have mean lions there and the .505 Gibbs side by sides are still in use, if you are lucky enough to have one. Cecil told me to get the slowest burning powder I could find. I found Hodgson 8700, a very slow burning powder, that proved quite effective. After I chronographed a few shots, Mr. Gibbs produced 9,720 pounds of muzzle energy at 2700 ft. per second. Remember, that's pushing a 600 grain slug.
I always told clients that if all else fails, we'll hide in the barrel!
