I tried this post in the guns forum, no response.

I just ordered a new scope setup and had a choice between steel rings and alloy rings. I went with steel rings. I know as a barrel heats it expandsit can put pressure on the stock and cause a deflection.Since the barreland the basesare steel, I was thinking that alloy rings would expand at a different rate as they heated and could cause a deflection in the scope alignment. Any thoughts?