Thanks for the replies, I also received a very detailed and informative reply from Buffalo Bore. It is a fairly simple question, will the older M29 safely handle the hotter, bigger loads of today. Yes, I realize that rifles are far, far more powerful than handguns. If I am carrying my 44 mag in grizzly bear country, I think I would want to carry the most powerful round that it could safely fire, kind of like everyone obsessing about the most powerful round they can carry in any kind of SD type handgun. Now, I have to admit that I haven't run across any dangerous large bear recently here in Central Texas, but......
Anyway, thanks again for the replies, and the response from Buffalo Bore was excellent and helpful.