Problem is - even cheap ASCM can easily outrange even the fanciest 76 mm shells.

Depending on guns means that ships will be within range of ASCM most if not all of the time.

Given the fact that such ASCM can be carried and launched from truck-mounted launchers that look just like plain containers, it's all but impossible to be absolutely sure that beaches are safe.

http://globalmilitaryreview.blogspot.com/2012/01/iran-test-fires-qader-noor-anti-ship.html?m=0 

"guns are a lot cheaper, and harder to intercept than a missile"

Cheaper, yes, Harder to intercept, hardly.

The article pointed out that missile guidance can be jammed.  A round is smaller thus harder to take out using typical anti missile tech.

Greg (N9NWO) said:

The article pointed out that missile guidance can be jammed.  A round is smaller thus harder to take out using typical anti missile tech.

It's also 1.8% accurate at combat ranges of 10 to 20 km in the Falklands. Guns are useful but not practical anti shipping weapons except in the most restricted waters.

Please read the article.  Against small craft the 57mm and 76mm are very effective.  And against some aircraft.  The Naval forces seem to be having larger calibers as it has increased from 20mm to 25mm and now 30mm.   But the 57mm seems to be gaining popularity as a mix between range and rate of fire.  Plus a single round is far less expensive than a missile.

OTOH, even at 57mm, a single round isn't enough to consistently engage a small boat.  Which is why things like ALAMO are being offered -- guided gun rounds (aka "gun-launched guided missiles") are often more cost-efficient than the many simple gun rounds required for the same Pk.  And one can probably have real arguments about the relative cost-per-kill of a 57mm gun firing ALAMO versus a Griffin missile (for example), especially when you roll maintenance and manpower costs into the discussion.

I noticed that the article talks about guns not being susceptible to countermeasures, but most naval guns are directed by radar or electro-optical systems (IR, TV, etc.) that can be jammed, decoyed, dazzled, or obscured.  

For ships with CIWS, gun shells are much easier to defend against than missiles. 

This led many analysts, strategists, navies and designers to consider the naval gun as an obsolete piece of weaponry which was unnecessary on a modern warship. Many ships during the 1970’s were built with a missile-only armament. However they had to find out the hard way that guns can never be entirely replaced by missiles and that both these systems complemented each other if used in the right manner.  This article analyzes the various modern guns in service today, their capabilities, advantages and the technological innovations which have made guns popular again.

ROLE OF MODERN NAVAL GUNS

As stated, guns complement the missiles and offer a unique set of capabilities. This has standardized the use of naval guns in several roles such as

• Anti-piracy : Guns of various calibers are typically used to engage pirate vessels. It would make little sense to use an expensive missile to blow up a boat. In many real life situations, 30 mm and 127 mm guns have been used to blow up pirate ships.
• Warning shots : In several situations, warning shots are fired by a naval guns to convey a strong message. This is not possible with missiles.
• Shore bombardment : During amphibious landings, naval gunfire support is provided and it involves firing thousands of shells in support of the landing troops. It basically acts as a naval howitzer in this role.
• Surface Warfare : This would involve the use of a gun to destroy another ship in a combat scenario. Typically a warship would engage an unarmed merchant  vessel/oil tanker. Direct engagement between warships using guns would be a last resort if no missiles are available.
• Anti-air warfare : Guns are surprisingly effective against incoming aircraft and missiles. Special types of guided ammunition with proximity fuzes and fragmentation shells are used to engage flying objects. Smaller caliber guns with high rates of fire are also extremely popular for this purpose although medium caliber guns are gaining popularity.
• Littoral warfare : Small and medium caliber guns with high rates of fire are popular in the littoral environment to engage fast-moving small-craft. Guns with guided shells are extremely effective in this role.

ADVANTAGES OF GUNS OVER MISSILES

As missile technology progressed and AShMs were made faster and deadlier, they became incredibly expensive as well. This called for a low-high end weapons combination of guns and missiles to tackle a variety of threats. Modern guns have far higher rates of fire when compared to their WW2 counterparts. The development of a variety of radar, optronic and IR sensors to guide gunfire has significantly improved their effectiveness and accuracy. The latest advancement in small-caliber guns is the incorporation of a remote-controlled turret which enables the operator to fire the gun accurately from the safety of the ship’s interiors. Most of these RWS (Remote Weapons Stations) have gyro-stabilized turrets which allows them to hit targets with ease even in rough seas. Also RWS are fitted with a variety of sensors to increase their accuracy further. Larger caliber guns have seen an advent of long-range guided shells which enable them to hit targets with precision at 50-100 km ranges. Such a thing was unimaginable earlier as the largest guns in existence had a maximum range of around 40 km with moderate accuracy. These features and advancements have made guns extremely relevant today. The advantages offered by modern naval guns over anti-ship cruise missiles are

• Cost effectiveness : An anti-ship missile is around 2000 times more expensive when compared to a large-caliber unguided gun shell. This matters a lot as most of the targets don’t require the use of a missile unless you are fighting a major war. Especially when engaging soft targets like small boats, guns are very economical.

Greg (N9NWO) said...

Shells cannot be shot down by missiles : The biggest advantage that large caliber gun shells ( 76, 100, 127 mm) have is that they cannot be shot down by the defense systems of the enemy vessel

That's a bold statement considering Sea Wolf demonstrated its ability to intercept 4.5" shells 40 years ago - one would hope that things have moved on since then. 
 

A shell, guided or not, has to follow a ballistic trajectory that will be both predictable and high above the horizon. Compared to a sea skimming missile it will be an easily tracked target and can be seen and engaged at a longer range.