Since the Hornet was developed back in the 20's, I would venture to say that you're alright with .224 bullets. My resources report that the Savage 23D(1923) was the first commercial gun available in the Hornet and after WWII, commercial gun production resumed and the .224 grove diameter was used. Your gun was produced between 1950 and 1953 and years after the war's end so load a few .224's and give it a whirl.