Artillery Organization

When the Marines defend their huge investment in Close Air Support, it’s largely because they need it. They simply don’t have a lot of tube artillery available for support. Why? Because they will never have enough amphibious shipping to move it.

The Army, on the other hand, has since the middle of the 19th Century had a long tradition of excellence in artillery, and accordingly places a lot of faith in a lot of guns.

Let’s compare some of the fire support available to a division. Organic to the Marine division is an artillery regiment. In the late 1980s and early 1990s, this regiment had three battalions of light artillery, 105mm tubes, and one battalion of 155mm artillery. All four battalions had towed pieces.

At first glance, Army artillery seems quite comparable.  A light division had “Division Artillery”~ effectively a brigade, with three battalions of 105mm guns, and one battalion of 155mm guns, all towed.   Seems pretty comparable.

But if we leave the light divisions, and look at the Army’s heavy divisions, we see a somewhat more robust organization. Each mechanized or armored division had a similar organization, but different armament.

Heavy divisional DivArty had three battalions of self-propelled 155mm guns (each with a self-propelled ammo carrier). It also had a battalion of self-propelled 203mm (8”) guns. Eventually, the 8” battalion would be replaced by a single battery of MLRS 270mm rocket launchers.

But the story doesn’t end there. Army divisions in Europe were intended to fight as a part of a corps, and indeed, as a part of a field army. And a great deal of the combat power of a corps or field army is located in units outside of the divisions. Each heavy corps typically had two separate artillery brigades, each with four battalions, usually three of 155mm and one battalion of MLRS, as they phased out the 8” tubes.

One of the key precepts behind US Army artillery doctrine has always been concentration. If it’s worth shooting at, it’s worth shooting at a lot. So it would be typical for the main effort of a corps operation to receive the support of both corps artillery brigades. And within that main effort  division, it would be typical for the maneuver brigade forming the main effort to receive the support of all the guns of both the division and the corps artillery, or at least a priority claim to their fires.* Conceivably, one maneuver brigade of three battalions would have the support of 12, or even more, battalions of artillery. That’s a level of fire support a Marine regiment commander could only dream of. And that doesn’t count the attack helicopter and Air Force tac air support our notional Army brigade might receive.  And because all these heavy artillery brigades were self-propelled, they could rapidly shift support from one area to another.

With the collapse of the Soviet Union, the Army no longer faces the spectre of a single division having to stem the onslaught of an entire Russian tank army. And the past decade of limited warfare in Iraq and Afghanistan has seen a much smaller need for massed artillery fires.

Instead, today’s artillery has shifted emphasis from massing fires to longer ranges and greater precision, via such tools as rocket assisted projectiles, guided unitary warhead MLRS rockets, and guidance kits for conventional 155mm artillery that permits a limited “boost/glide” profile.  The battlefield a single maneuver brigade occupies is much larger than in years past, even as little as 20 years ago. And simply to cover that area, the supporting artillery either needs a longer range, or the greater lethality of guided rounds (that way, smaller units of artillery, such as a battery or even just a platoon can disperse over a wider area to support more units and cover more battlespace).

*I’ll leave it to URR or Esli to explain the doctrinal niceties of attached, OPCON, Direct Support, General Support, or General Support Reinforcing.

Tank Battles

I’m feeling poorly today, so here a “best of..” post from way back in the very early days of the blog.

I wrote earlier about bringing enough gun to the fight, but not too much. A prime example of this was the M-1 Abrams tank.

When this tank debuted, people were aghast at the cost. What they didn’t realize was it was acutally the result of an extreme cost cutting program. For 20 years, the Army had been cooperating with Germany to develop a sucessor to the M-60 series of tanks, but each iteration had become too complex and too costly. The Army finally decided that they would develop a tank using technology shared with the Germans rather than develop a tank to be used by both countries.

One of the sticking points was the main gun. The standard US tank gun was the 105mm M68. The Army thought this was sufficient to defeat current and projected Soviet armor (and were pretty much right).

The Germans had developed the excellent 120mm smoothbore, and wanted both countries tanks to use it. Our Army resisted for a couple of reasons. The biggest was cost. The new gun would have to be license produced here, with associated setup costs. Even more expensive would be providing stocks of ammunition for the gun. The Army had a huge stockpile of 105mm ammunition already. Buying an entirely new stockpile in the tight budgets of the 1970s wasn’t an attractive option.

In the end, the 105mm won-sort of. The decision was to place the M-1 into production with the 105mm, but make provision to add the 120mm in the future. As it turned out, for various reasons, this was a lot harder than anyone expected. Still, partly as a sop to our German allies, and partly over concern about the ability of the 105mm to defeat future Soviet armor, the 120mm was adopted for the M1A1 that entered service in 1988.

One disadvantage of the 120mm was a reduced ammo load. An M-1 with the 105mm carries 55 main gun rounds. An M-1A1 carries 40. As it turns out, however, few tanks will shoot their entire basic load in a single battle. In fact, not a single tank in Desert Storm fired its entire basic load.

Tankers, ever wonder why the coax on your tank has that massive 4000 round load? Because that’s where the designers originally wanted to put the 25mm M242. The only reason it didn’t make it into the final design was cost. Leaving the 25mm out saved about $100,000 just for the gun, and made the fire-control system simpler, and hence cheaper. 

Tank Battles

I wrote earlier about bringing enough gun to the fight, but not too much. A prime example of this was the M-1 Abrams tank.

When this tank debuted, people were aghast at the cost. What they didn’t realize was it was acutally the result of an extreme cost cutting program. For 20 years, the Army had been cooperating with Germany to develop a sucessor to the M-60 series of tanks, but each iteration had become too complex and too costly. The Army finally decided that they would develop a tank using technology shared with the Germans rather than develop a tank to be used by both countries.

One of the sticking points was the main gun. The standard US tank gun was the 105mm M68. The Army thought this was sufficient to defeat current and projected Soviet armor (and were pretty much right).

The Germans had developed the excellent 120mm smoothbore, and wanted both countries tanks to use it. Our Army resisted for a couple of reasons. The biggest was cost. The new gun would have to be license produced here, with associated setup costs. Even more expensive would be providing stocks of ammunition for the gun. The Army had a huge stockpile of 105mm ammunition already. Buying an entirely new stockpile in the tight budgets of the 1970s wasn’t an attractive option.

In the end, the 105mm won-sort of. The decision was to place the M-1 into production with the 105mm, but make provision to add the 120mm in the future. As it turned out, for various reasons, this was a lot harder than anyone expected. Still, partly as a sop to our German allies, and partly over concern about the ability of the 105mm to defeat future Soviet armor, the 120mm was adopted for the M1A1 that entered service in 1988.

One disadvantage of the 120mm was a reduced ammo load. An M-1 with the 105mm carries 55 main gun rounds. An M-1A1 carries 40. As it turns out, however, few tanks will shoot their entire basic load in a single battle. In fact, not a single tank in Desert Storm fired its entire basic load.

Tankers, ever wonder why the coax on your tank has that massive 4000 round load? Because that’s where the designers originally wanted to put the 25mm M242. The only reason it didn’t make it into the final design was cost. Leaving the 25mm out saved about $100,000 just for the gun, and made the fire-control system simpler, and hence cheaper.