The autofire of the Weatherbys was a German problem. They used a spring that didn't have enough tension to hold the sear back. Over time it would stretch so that if the trigger was pulled on safe the rifle would indeed fire when the safety was release.

I don't think it was ever a problem of being bounced around but more of a problem of people screwing around.

I have a 20 year old 340 that has been around the world and through the bush as much or more than most with never a problem. Unless you count the magazine falling open and dumping the cartridges on the ground a couple of times. A stiffer spring fixed that also. A stiffer spring fixes most problems, haven't you noticed?