In the 1860s rapid changes were taking place in the technology of armament production, and calibres were increasing by about an inch per year.
ɪnðə wˈʌn θˈaʊzənd ˈeɪthˈʌndɹɪd sˈɪksti z ɹˈæpɪd tʃˈeɪndʒᵻz wɜː tˈeɪkɪŋ plˈeɪs ɪnðə tɛknˈɑːlədʒi ʌv ˈɑːɹməmənt pɹədˈʌkʃən, ænd kˈælɪbɚz wɜːɹ ɪŋkɹˈiːsɪŋ baɪ ɐbˌaʊt ɐn ˈɪntʃ pɜː jˈɪɹ.