They were in fact so effective that a very common rumour in the German armed forces was that the Americans had invented some sort of fully automatic artillery, like something out of “Total Annihilation” that could spray shells like a machine gun.
Things like the Tiger tank, Spitfire, and other fancy-pants weapons get all the glory, but the most effective weapons system of the Second World War was American artillery deployed in the latter stages of the war.
American Artillery was the best in the business (with the possible exception of Eight Army Arty at El Alamien). The Germans had their tanks, the British had their infantry, the US had its big guns.
yo,this is pretty impressive, and it is only one firing …
Particularly, the coordination of US artillery was unmatched by other WWII participants. More people were trained to, and authorized to, call down fire missions than in other armies, and the arty would respond to requests from a wide variety of American units, not just its central command. Lots of individuals could be “spotters” on a moment’s notice, and call in fire from any ready surrounding artillery units, even those of different commands.
The net result of this was that American units regularly drenched the enemy with shells on a moment’s notice at tactically opportune times. This created the impression among their enemies that the Americans had much more artillery than they actually had, which was even more demoralizing to think about.
To clarify, the reason this was so is because the rockets do not have the recoil of conventional artillery, so they can be mounted to unreinforced platforms, including aircraft.
I have read similar remarks by Army people dismissing aircraft as of being no use at all just really really expensive and less effective artillery.
Projectiles cost less and the ratio of HE (or other payload) vs. structure is higher for rockets versus artillery of similiar calibers/dimensions. Rocket warheads have considerably less stress during launch and flight. An artillery projectile experiences thousands of “Gs” compression when fired and axial loads (twisting of the body) of nearly the same magnatude. Projectile failure in the artillery tube is often fatal to the gun crews. High strength metals and composites are used. Heat treatment is carefully monitored to get the desired strength, elasticity, and fragment characteristics. In submunition bearing projectiles, the payload material must also stand up to launch forces. The US 155mm DPICM round has the bottom four layers of submunitions designed differently to withistand compressive forces from an artillery launch.
The rocket projectile walls and base are much thinner and can be manufactured out of less costly materials. Ideal for less technologly advanced countries/factions.
I thought of mentioning the extra structural strength that artillery shells have to carry around, but I was wondering how much of that is offset by the rockets needing to carry fuel.
Most propellant would burn off in the tube or shortly after launch so that weight wasn’t part of the downside. Rockets do drag the motor casing the entire way to the target resulting in decreased range. For a cheap barrage weapon, it wasn’t worth designing/adding a mechanism to separate the motor from projectile after launch. (Some missiles on the other hand, …). You would have rocket motors raining down on your own troops and, if the separation mechanism didn’t work, short rounds with the now armed warhead coming down short on the good guys.
The much cheaper manufacturing techniques and materials plus the payload/total weight ratio were strong points for rockets. Tougher to vary the range though. Accuracy with artillery with different zone weight for projectiles and different propellant weights was better. You could compensate for weather conditions, gun tube wear, firing / tube temperatures with the artillery.
Modern artillery firing is quite advanced. I’d marvel at a two tube battery supporting multiple fire missions at ranges approaching 55km. The guys would fire a couple of rounds in one direction; swivel around to another heading; fire two more rounds. After a couple of minutes (yeah - firing to impact was measured in minutes at those ranges) get feedback on accuracy of the first two; make corrections and refire; go back to second mission - or a third. Amazing.
You can get a lot more steel on target with the MLRS (multiple rocket launcher system) in a much shorter time than with conventional tube artillery. Yes, you can load them a lot faster too.
a.
Err…you can?
MLRS take nine minutes to reload (cite) and that is a system that was designed to be a fast reloading mobile rocket system.
I am reasonably certain that any tube artillery can reload a lot faster than that (well, maybe not the likes of the Paris Gun or some crazy thing). The MLRS carries 12 rockets so 45 seconds per shot if you want to divide it out that way (doesn’t work like that, this is just for comparison). Again tube artillery is almost certainly going to be firing faster than once every 45 seconds when going full out. Even battleship guns could fire faster than that.
Army people would say that. 
(And I’m ex-Army.)
Modern warfare between professional armies is all about combined arms. Rocket artillery has a specific purpose, howitzers another, anti-tank guns still another. Various type of aircraft have even more purposes; it’s literally true that a bomber is essentially just a very expensive artillery delivery system, and the weight of ordnance versus cost ratio is terrible… but an airplane can fly much, much further than any gun can fire.
You can’t sell all your planes for cannons because then you can’t bomb anything further away than 20 miles or so. You can’t sell all your tanks for infantry because then you have no armored support, and you can’t sell all your infantry for tanks because then what do you do if you need to fight in a jungle or a city? Every part of an armed forces has its little role to play.
Rocket artillery did not replace anything, it just offered armies a new way of delivering shells, that fit a specific need.