The next time you need to carry a Mamoth mandible you should consider an Alaska Freighter Frame . They are much favored by Alaskan big game guides for hauling out meat, moose racks, and other brutally heavy and/or awkward loads. I believe they are only available from Barney's, a local outfit here in Anchorage. Barney's builds them to be totally indestructable. I have one that has served me well in the past. In my old age I don't do so much of that kind of heavy weight packing anymore so it doesn't get used very often these days.

I have no connection to Barney's, but I can recommend their gear.