Koolmoose said:
I was thinking of stainless AR's for around the world crusing in a high humidity environment in a slow trawler that would be an easy target for pirates.
Stainless steel still corrodes, it just corrodes less easily than other steels. I'd be willing to bet that a traditional mil-spec anodized aluminum-receiver AR would hold up better to corrosion than a stainless steel one, even in a marine environment.
On both of my Marine Corps infantry MEU(SOC) deployments, our company was the boat company, tasked to perform Zodiac boat raids. I cannot begin to count the number of times I fully submerged my M16A2 in salt water and then didn't get a chance to clean it until many hours later. And I don't remember ever experiencing any corrosion on the upper or lower receiver.
As others noted back in 2012, the only advantage of an AR with a stainless steel receiver would be increased weight and (subjectively) better looks. On a rifle you carry all the time (like you would if you were worried about a pirate attack), the former is a large disadvantage, and the latter isn't much of a priority.
