Many very experienced metallurgists will argue that stainless loses no more strength than chrome moly at low temperatures.Due to the added corrosion resistance that stainless provides, our company uses a great deal of stainless steel at our plant in many applications where strength is very important.We often experience -40 and don't have any strength problems with stainless steel failing.
I refer you to Krieger Barrel and click on the profiles tab and go to the bottom of the page.