[OKSooner]

I’ve seen that piece of Yamato armor numerous times. It wasn’t struck by 16” Superheavy AP fired from a 50 caliber Iowa class rifle, it was struck by a standard 16” AP fired from a 45 caliber Washington/South Dakota class rifle.

Could someone explain the nomenclature of the calibers used in these big naval guns, particularly the part about ".45 caliber", ".50 caliber", etc?

TIA.

[tanknetter]

Could someone explain the nomenclature of the calibers used in these big naval guns, particularly the part about ".45 caliber", ".50 caliber", etc?

Caliber is defined as rifle length divided by bore diameter. In the case of the Iowas their rifles were 50x the diameter of their 16" bore, or just about 67 feet long.

The preceding Washington and South Dakota classes' guns were 45x their 16" bore, or 60 feet long. The extra 6' in length made a big difference in both distance and accuracy.

I've been aboard the Wisconsin (Iowa class) and the North Carolina (Washington Class) and my own Mk.I Eyeball observations are that the 6' difference is really noticeable - the North Carolina's guns look ... stubby ... compared to the Wisconsin's.