IIRC, based on my limited knowledge of nuclear weapons, Little Boy contained HEU close to 88%. However, some amounts were only enriched to 50%, with the average enrichment of uranium in the weapon being around 80%. What happens if Little Boy is produced with uranium to be enriched more higher? I know some uranium produced around Oak ridge was around 90% while the remaining had varying percentages of around 20-70%. What if Little Boy's enrichment of uranium was over 90%? Does this increase the weapon yield? I know it wouldn't be a huge yield difference, but I noted that some gun-type nukes in the late 40's by the US had a yield around 25-30 kt. Was this due to a higher percentage of uranium used or a variety of other factors involved? (I am aware that the gun-type was an inefficeint design, but in this scenario, all work is directed toward a gun-type uranium weapon instead, meaning no thin man or fat man at all.)