A search of these forums or Yahoo web search didn't turn up anything useful about this .44Mag ammo for handguns. I'd like to know more because of the following question I sent to Smith & Wesson, and their reply:
Dear Smith & Wesson,
I am the satisfied owner of a 329PD, which I carry while hiking and fly fishing in Alaska. ...I [read] a posting found on an Outdoors website, raising the question of safe loads for this pistol. ...am currently carrying Alaska Backpacker ammo, 320gr GC Hard Cast cartridges in .44Mag for this pistol…
1. Will shooting this load void my warranty?
2. Have there been "break the gun" issues with heavy factory loads?
RESPONSE from Smith & Wesson: "Hi. as long as the ammo you choose meets S.A.A.M.I.E. specs you can use it in our guns."
I couldn't find enough information about SAAMIE specs (http://www.saami.org/) for my Alaska Backpacker, 320 gr. Hard Cast ammo. In fact I couldn't find anything online about these rounds.
Unless I find more information, I will probably switch to CorBon or Buffalo Bore. I wonder if anyone has a lead on this ammo and whether it meets these SAAMIE guidelines?