I'm searching for some clarification regarding what Rav Moshe Feinstein, z"l, held with regard to chodosh in chutz la'aretz. My father-in-law recently attended a lecture of a student of Rav Reuven Feinstein, shelit"a, who claimed his father relied on the opinion that it is only a Rabbinic prohibition outside of Israel. However, my understanding of his responsum on the topic (Igros Moshe YD 4:46) is that he only relied on a double uncertainty where such was available, implying he held it was a biblical prohibition even in New York. What is further baffling is that the responsum is actually written to Yosef Herman who puts out the popular Chodosh Guide based on the assumption that there is no reliable double uncertainty. (I tried to contact Mr. Herman but never received a reply.)
Rabbi Yehuda Spitz cites the ruling as a qualified leniency:
See also Shu”t Igros Moshe (Y”D vol. 4, end 46) where although he maintains there is what to rely upon l’maaseh, maintains that still one should try to ascertain where he can purchase yoshon flour, as it is preferable.
I'm curious if anyone can shed light on what the reality was in terms of the plausibility of the presence of chodosh in the kosher market up to and including the time of the responsum, and/or whether Rav Moshe changed his mind at any point regarding what if any leniencies there were, both in his personal practice and in his rulings for others.