Good to know, Halk. Ithaca produced the LeFever Nitro Special from about 1922 to 1948, I think. Years ago, I had a 20 ga. Nitro Special, 28" barrels and non-selective single trigger- great grouse gun with open chokes-- My former hunting partner and next door neighbor bought it from me, for his teen-aged son to bird hunt with--after about 3 years of me "loaning it to his lad" and apparently he shot it quite well.

Your Dad's Nitro must have had tightly choked barrels for him to score that well at trap- 16 yard line--Back in the day, when I shot trap, Win. Model 12's were "King", but the Ithaca "Knick" single barrel trap gun was also often seen, also over-unders.
The confidence a man has in his gun, no matter what make or model, often has a lot to do with how well he scores with it.

"The field is the touchstone of the man"..