Superior long range artillery in World War II

Although Soviet artillery bombardments are often described as “massive, powerful, earth-shaking …”, U.S artillery was the best in terms of both strength and effectiveness.
In the book Dirty Little Secrets of World War II, the authors discussed in detail the various aspects of US artillery and the reasons that made it the best in the world in WW2.
A big U.S. Army advantage in ground combat was its innovative methods of controlling and coordinating artillery fire. This was no accident. Throughout the 1930s, American gunners improved their equipment and techniques to the point where the United States had the most effective artillery in the world. This success sprang from several sources:
Weapons. America designed new guns after World War I and had them ready for mass production when World War II began. The standard 105mm howitzer was based on the German gun of the same caliber used in World War I, but the American version was much improved. Guns of other calibers were of equally high quality.
Mobility. The decision was made to dispense entirely with horse-drawn guns, something most other armies did not do until after World War II. All U.S. artillery would be towed by trucks or be self-propelled (sort of like a tank, but without the armor and turret).
Fire Control. This was the biggest breakthrough. A combination of advanced computing techniques (with mechanical computers) and lavish use of radios gave U.S. artillery the ability to be more flexible than that of any other nation. In the past, and for most nations during World War II, guns were aimed and fired according to a carefully prepared plan. This was acceptable if the enemy operated according to your expectations, but this was often not the case. Forward observers (FOs) had been used since World War I, but in that war they would call back instructions for only a few guns (usually a battery of four to six guns or a battalion of twelve to eighteen). The American innovation was to allow the FOs to call upon the fire of “all guns within range.” U.S. artillery units practiced this constantly and this enabled their fire to be concentrated quickly, accurately, and massively. Even the Germans were impressed by this, but they were unable to duplicate the American techniques during the war.
Ammunition. America was a manufacturing giant and millions of tons of artillery ammunition was produced and rapidly sent to the guns at the front using the equally numerous military trucks the United States turned out. Not only was American ammunition abundant, but it was of high quality, with a wide variety of specialized shells.
Aircraft. Artillery units had their own single-engine aircraft (militarized Piper Cubs) to carry FOs aloft. From these heights, targets could be spotted and fire adjusted. Even fighter pilots could be impressed in an emergency to call in artillery fire. The wide-spread use of spotter aircraft ensured that there were few enemy targets that went unseen, and unhit.
To the enemy, American artillery seemed to be everywhere, all the time and in unbelievable quantity. And should the enemy launch an attack, every American gun within range would, as if by magic, begin firing on the advancing troops. The result was that both the Japanese and Germans were surprised, and usually pulverized, when they encountered the artillery support that accompanied U.S. ground units. The Germans thought this massive artillery support was somewhat “unfair” (if only because the Americans had it and they didn’t), while the Japanese found yet another way to die nobly.
(In this answer, I define “long-range artillery” as “launching a projectile without a direct line-of-sight between the gun and its target” (i.e. indirect fire or fire in covered position) and therefore requires artillery observers. )artilerru
In terms of mobility, both the Germans and the Soviets weren’t very mechanized and relied heavily on horses to tow their artillery. The Germans never had enough trucks. Between the battles in Russia and the Allied invasion of France in June, the Germans lost 109,000 trucks. This was 39 percent of what the German armed forces had and equal to their entire production during 1943. About three quarters of the transport in their army was horse-drawn. In World War 2, the Germans lost 2.7 million horses.
German horses stuck in Soviet rasputitsa.
The Soviets received about 430,000 trucks from the U.S as part of the Lend-Lease program but that wasn’t enough because the entire Soviet automotive industry was turned over to tank production. They ended up relying strongly on horses to move artillery and supplies around, although to a somewhat lesser extent than the Germans.
US Studebaker trucks used in the Soviet Union during WW2
In Stalingrad, thousands of German guns were left to the advancing Soviets because the 6th Army couldn’t take the guns with them as they retreated into the city. The Soviets, on the other hand, found it extremely difficult to move heavy artillery with the forward units to take out German bunkers and fortifications in the city. After Stalingrad, the Soviet started designing and producing heavy self-propelled guns such as the SU-152 and ISU-152.
The SU-152 self-propelled gun was initially designed to help the infantry destroy enemy fortifications. But it turned out that the enormous 152mm high explosive round it fired could destroy pretty much anything it hit. And so this SPG was also used as an anti-tank weapon.
In terms of fire control, both the German and the Soviet FOs couldn’t call upon the fire of “all guns within range” like U.S could.
In terms of ammunition, both the Soviets and Germans suffered from ammunition shortage, especially artillery shell, on many occasions such as in the battle of Stalingrad and the siege of Sevastopol. The Soviets had a larger production capacity compared to the Germans and they actually produced quite a lot of artillery shells, but they also wasted lots of them on long yet ineffective initial bombardment at the start of each offensive. Why were they ineffective? Because the Germans often guessed correctly when the Soviets would unleash their opening barrage and evacuate their first-line positions just before the barrage began. One case in point was the massive artillery barrage on the 16th of April 1945, signalling the start of the Berlin Offensive, the Soviet fired more than 1 million artillery shells in a few hours on all but empty German trenches.
(Now to be fair, in many battles Soviet opening barrage did wipe out German defenses. For example in the Vistula-Oder offensive, when Soviet artillery opened fire, the Germans hurriedly withdraw from the first line to the second line, they expected a long bombardment on the empty first-line trenches. But this barrage lasted only 10 minutes, Soviet artillery spotters were pushed forward and they detected the German movement. The Soviet guns then opened fire again, pulverizing the second line of German defenses with all of their remaining ammunition. This second barrage lasted 1 hour and 47 minutes, and its effect was shattering, everything inside the German 10-mile deep defensive zone was obliterated.
Soviet artillery also played a crucial role in smashing formidable German fortifications infestungs (or fortresses) like Poznan and Konigsberg.)