grenade launcher vs. cannon

[cameron]

Forgive me if this question has been asked before but I've been wondering, what are the relative advantages and disadvantages of a cannon compared to a grenade launcher?  For example, an armoured vehicle equipped with a 40 mm cannon as opposed to one equipped with a 40 mm grenade launcher?

 

[63 Delta]

A 40mm cannon would have a higher rate of fire, higher penetration, better distance, more accuracy and a more varied type of ammunition.

For example a 40mm cannon can shoot APFSDS (Armour Piercing Fin Stabilized Discarding Sabot) Rounds which could penetrate many armour types. It could also shoot HEI (High Explosive Incendiary) Rounds as well, which would have the same type of effect as a grenade would. A 40mm would also be able to accurately hit targets at ranges of around 2000m. More of a direct effect.

Were as a 40mm grenade launcher, in Canada at least, really only uses one type of ammo which is a HE (High Explosive) Round. The M203 doesnt really shoot that far (400m ish if I remember right?) is very much an area weapon, and is slow to load. Of course a mounted C16 GL can shoot sustained fire at further distances, but will still not be as good as a 40mm cannon for hitting armoured targets. It would be good at suppressing large groups of infantry and columns of soft targets such as supply trucks.

Hope that answers some of your questions. Both are useful in different ways.

As for my experience and knowledge... I was an C8/M203 gunner overseas, and a 25mm gunner qualified.

 

[Fishbone Jones]

Range, accuracy, rate of fire and variety of ammunition just to name a few.

M203 - point target = 150m, area = 350m, max 400m 5 to 7 rounds per minute http://www.colt.com/Catalog/Military/Products/ColtM20340mmGrenadeLauncher.aspx#102963-technical-specifications

CTA 40mm cased telescopic cannon - approx. 2500m w/ APFSDS-T, 180-200rpm http://www.thinkdefence.co.uk/2011/12/cta-40mm-cannon-brochure/

 

[cameron]

Thanks guys, these replies were very helpful.

 

[McG]

Rate of fire is not necessarily a difference between grenade launcher and cannon.  The rate of fire will be designed into the weapon based in a number of factors.  You can find similar rates of fire between an automatic grenade launcher and a medium caliber cannon designed for ground engagements.  The difference in the cannon is muzzle energy (equating to flatter trajectories over longer distances with shorter time of flight), the ability to fire KE penetrators, and (typically) longer & heavier HE projectiles.

It should be noted that grenades come in high and low velocity variants (compare under slung rifle grenades to grenades of vehicle mounted AGLs).  Cannons can also be designed to use ammunition of either high or low velocity.  High velocity AGL is still less KE than a low velocity cannon, but the clear distinction does begin to blur ... And I cannot think of any production low velocity cannons.

 

[Scoobie Newbie]

MCG just dropped some knowledge!

 

[a_majoor]

Rate of fire is not necessarily a difference between grenade launcher and cannon.  The rate of fire will be designed into the weapon based in a number of factors.  You can find similar rates of fire between an automatic grenade launcher and a medium caliber cannon designed for ground engagements.  The difference in the cannon is muzzle energy (equating to flatter trajectories over longer distances with shorter time of flight), the ability to fire KE penetrators, and (typically) longer & heavier HE projectiles.

It should be noted that grenades come in high and low velocity variants (compare under slung rifle grenades to grenades of vehicle mounted AGLs).  Cannons can also be designed to use ammunition of either high or low velocity.  High velocity AGL is still less KE than a low velocity cannon, but the clear distinction does begin to blur ... And I cannot think of any production low velocity cannons.

Recoiless cannons like the Carl Gustave, Russian 82mm's and US 106mm's are low velocity weapons (the British 120mm WOMBAT is probably the largest recoilless rifle ever in service, but long out of service). Breach loading gun/mortars like the 60mm Brandt, Russian 2B9 Vasilek and the ones used in the IDF on board AFV's also would be considered low velocity cannons. The AMOS 120mm breach loading mortar system is probably the largest in prototype or service.

That said, they would have most of the disadvantages of a grenade launcher (high trajectory, short range, long time of flight etc), but on the plus side they have much larger warheads. The "Boom" on the far end is much larger and more effective than a 40mm AGL. The Russians strapped 2B9's to the back of AFV's in Afghanistan to have a versatile fire support vehicle, the US Armt experimented with the 2B9 on the back of an HMMVW, and AMOS systems have been demonstrated on LAV class AFV's to provide the same effect