Naval Historywith Dr. Alex

Q&A · 3:29:29-3:34:33

How long can a practical naval gun barrel be?

The practical calibre length of a naval gun depends on bore size, because a ratio that works for a five-inch weapon becomes an enormous structural burden for a battleship gun.

Battleship GunsGun BarrelsNaval GunneryWarship Design
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Question

How long could a practical naval gun barrel be, and were 16-inch/60 guns planned?

Short answer

Small guns can use longer calibre ratios, but very large guns quickly become unwieldy; 45 to 50 calibres is the more practical historic balance for battleship weapons.

Notes

The exchange explains why 45- to 50-calibre barrels were a recurring balance point for large naval guns. More length can raise velocity, but it also adds barrel weight, mounting loads, manufacturing difficulty, and handling problems. A 16-inch/50 is already roughly 68 feet long as a complete weapon, whereas a 5-inch gun can reach 70 calibres without becoming physically comparable. The HARP experiments technically produced an extremely long 16-inch system by joining barrels, but that was not a practical warship weapon. Calibre length must therefore be judged together with bore diameter, metallurgy, and intended mounting.