I understand that some early .30-06 military rifles were subject to unreliable heat treating, and actions on such early issue rifles can be subject to catastrophic failure when shooting "high power" rounds. What is a "high power" round? Something more powerful than your average ordinary .30-06 commercial off-the-shelf loading, for example a handload that is pushing the upper edge of the envelope. I think this is a matter that can be resolved objectively based on the serial numbers located on the actions. Seems like serial numbers less than about 240,000 are subject to this possible flaw. Doesn't mean every one of these low number actions will fail, but some will -- it is a variability in manufacturing that was not understood well at the time of early production. Others of greater erudition in this subject can probably provide further guidance on this subject -- I'm reciting this information from memory, and it may not be entirely spot on.
There's a whole lot of controversy sorrounding the 'low number springfields' -some claim they are safe to shoot with the idea if the receiver was weak, it would have blown up long ago, others say they are a grenade just waiting to go off. Noone really knows how many were made, a few were found brittle from over herat treating and a few more actually blew up with use. There was a cut-off point with the serial numbers from Rock Island Armory and Springfield armory where the heat treating was standardized, and everything before these numbers were potential weak receivers, though its likely that out of the several hundred thousand low number receivers, its likely than a relatively small percentage were dangerous.
The Remington (along with other manufacturers) 1903A1s and 1903A3s were made later and didn't have this problem.