Comments here:
http://www.m4carbine.net/showthread.php?141291-Stainless-Steel-Barrels-410-vs-416-vs-416R
"In conclusion, if you are in the market for a stainless steel rifle barrel I would offer the following recommendations:
Avoid lightweight or thin profile stainless steel barrels. This recommendation is echoed from multiple barrel manufactures due to the potential issues with temper embrittlement in martensitic stainless steels. The thicker walls of a medium, heavy, or bull profile barrel will strengthen the barrel and make up for the shortcomings of 400-series stainless steels as a barrel steel.
Avoid standard 416 stainless steel barrels. 410 and 416R stainless steels both have a lower sulfur content, making them less prone to developing sulphide stringers which may result in catastrophic barrel failure.
If the rifle will never see freezing temperatures, 410 stainless steel will likely be your best option. 410 stainless steel has the lowest sulfur content of the three grades we discussed, and will be the least likely to develop sulphide stringers. Avoiding sub-zero temperatures and using a barrel of adequate thickness should also minimize the temper embrittlement issue.
If the rifle may see freezing temperatures, 416R stainless steel will likely be your best option. 416R stainless steel is rated for use at temperatures as low as -40 degrees Fahrenheit and has a lower sulfur content than standard 416 stainless steel. However, you should still ensure the barrel is of adequate thickness."
I don't know who these multiple barrel manufacturers are, but I would like more info before I purchase.
M