What are the advantages of a smooth bore cannon used on most modern tanks? Wouldn’t rifling in the barrel improve accuracy, range and reduce potential tumbling of the projectile?
Answered by: Gary Zhang,lives in Australia
Smoothbores for the most part are just straight up better
Nowadays, the better cannons are generally the ones that are smooth-bore. Rifled guns are still in use, but technology has caught up that allows the advantages of Smooth-bore guns to come into play while mitigating the disadvantages.
Rifled guns were originally the mainstay of the majority of tank cannons. The biggest advantage that they provided was that they were consistently more accurate than tanks with smoothbore guns. This is because the rifling inside the barrel spins the shell as it is fired, stabilizing it and making it more accurate.
An example of rifling in the 105mm L7A1 gun
105 mm L7A1火炮来复线一例。
Nowadays, the British use a Main Battle Tank with a rifled gun specifically because they place special importance on their HESH(High Explosive Squash Head) shells. These shells are filled with a plastic explosive and a delayed base fuze. When, impacting against a surface, the plastic explosive will spread out and then explode, which could potentially cause catastrophic structural damage. Indeed, this shell was noted for being extremely useful against buildings and lightly armoured vehicles.
This kind of round is unable to be fired by smoothbore guns which is why other countries have done away with this kind of ammunition. Currently, only the British Challenger 2 uses such a round. It should be noted that the Indian Arjun tank also has a rifled gun. Other than that, no other tanks fielded by other major nations use rifled guns.
Smoothbore guns have the advantage of being better suited to firing fin-stabilized armor piercing rounds. There is also the added benefit of the barrels being able to last longer with reduced barrel wear compared to rifled guns.
The biggest difference between smoothbore and rifled guns is the secondary ammunition they can fire. A smooth-bore gun is ideal for firing HEAT(High Explosive Anti Tank) rounds. A rifled gun can fire specially designed types of this ammunition but it is generally cheaper and easier to use a smooth-bore.
The reason why rifled guns have all but disappeared is because that smoothbore guns simply have so many more advantages. They are better suited to firing specific types of ammunition especially the APFSDS(Armor Piercing Fin Stabilize Discarding Sabot) rounds which are currently the best option when it comes to anti-tank performance. These rounds have fins on them which stabilize the round anyway removing the need for a Rifled gun.
Combine this with being better suited to fire HEAT rounds, reduced barrel wear and negligible loss of accuracy compared to rifled guns, the smoothbore guns simply have a large number of benefits compared to the downsides that technology has mostly eliminated anyway.
Smoothbores are simply better right now.