Having dug myself a very deep hole in this area, I am going to take the advice of the ancients and quit digging.
I did notice your concern about proliferating ammo types 2B. I don't know if you have seen this information. It concerns a Multipurpose 120mm round with a programmable fuse.
http://www.nationaldefensemagazine.org/issues/2005/sep/uf-army_developing.htm
Army Developing Advanced Ammo for Abrams Tank
By Joe Pappalardo
To be more useful in urban battlefields, the Army's main battle tank needs to be armed with advanced multipurpose rounds that can be adapted for use against different types of targets, officials said.
"Overall, that is where we need to be going," said Army Col. Mark Rider, project manager for maneuver ammunition systems.
"Kinetic-energy rounds are being sent to the rear," Rider noted. "From a logistics and operational standpoint, our tankers have to have the ability to ... make them multipurpose. There will be fewer specialty rounds."
As the war in Iraq shifted from limited armor engagements to counter-insurgency, tank units rediscovered their roles in urban combat. Current ammunition, however, is better suited to defeat hordes of Cold War-era Soviet tanks, rather than insurgent guerillas dug into houses and bunkers. A multipurpose round would offer tankers flexibility to target not only armored vehicles but also foot soldiers or light trucks, even if they are shielded by a rock wall or within a fortified concrete shelter.
The Armament Research, Development and Engineering Center at Picatinny Arsenal, N.J., is developing line-of-sight multipurpose (LOS-MP) munitions that would replace four rounds currently used in Army and Marine Corps tanks.
The new round uses a fragmenting warhead and programmable fuses that can be set for either point-detonation against hard targets or for airburst, to strike soft targets. The fuse settings are controlled via datalink and operated by the tank crew with a mouse click.
"One size fits all-that's the best way to put it," said Ernie Logsdon, division chief of the Munitions Systems & Technology Directorate at Picatinny.
The LOS-MP program started in 2004. "I think the urban tank experience in Iraq emphasizes the need for this round, especially for the Abrams tank, although the request did not start this way," Logsdon said, explaining that the program was designated originally for the Future Combat System's mounted combat vehicle, which is not scheduled to enter service until at least 2014. The Army decided to accelerate the development of LOS-MP, so it can be fired from Abrams tanks.
If funded to completion, the LOS-MP would replace the M830, M830A1 and M908, as well as the just-released M1028 canister round.
The M830A1 is a high explosive shot with a limited antipersonnel component, and tank crews must flick a switch manually for the round to be used against enemy helicopters. All the other current Abrams rounds are what the Army calls "dumb bullets."
The M908 was initially developed in 1996 to destroy obstacles, such as bunkers. The round penetrates concrete before detonating.
The M1028 canister round has only recently been available to Army and Marine tank crews in Iraq. The round, fired from the main cannon, contains tungsten balls that fan out into a 500-meter lethal shotgun blast.
In January, General Dynamics Ordnance and Tactical Systems was awarded a $5.8 million contract for low-rate production of 3,600 M1028 rounds. The company will assemble the projectiles at its facility in Red Lion, Pa.
Although new, this canister would be replaced, along with its three brethren, by a single multipurpose round. The Maneuver Armament Systems and ARDEC together are designing two different versions; the full-bore XM1069 and the sabot XM1068.
The full bore is more lethal at close ranges, while the sabot has a smaller diameter, fewer explosives and better reach.
"If the user requirements come in and they want a longer range, we'll go with the 1068," said Logsdon. He said both versions of the multipurpose round offered as good or better lethality as the rounds they would replace.
LOS-MP would not be the preferred munition for direct tank-on-tank battles. Kinetic energy rounds would be loaded for such an engagement, according to Pete Cardell, deputy product manager for maneuver ammunition.
There are no tungsten balls or other projectiles in LOS-MP. Instead, the warhead is designed to come apart into whirling chunks of shrapnel when it is set to the airburst mode. Unlike the current canister, it would be lethal and accurate at long range.
One eager customer for new types of ammunition is the Marine Corps, which has operated the 70-ton Abrams since the early 1990s. Marines have been involved in the development of both the canister round and LOS-MP, Lodson said.
Having a multipurpose round in the arsenal has many benefits, boosters at ARDEC said. The logistical footprint of a multipurpose muniton is smaller and easier to track in the transportation cycle. A successful LOS-MP would "wipe the logistics burden away. We'd be going from five rounds to two," Logsdon said.
Other advantages come in the procurement process. By consolidating the rounds, the military would increase the size of the munitions orders. In theory, that would lower the price per round.
Since the tanks only hold 40 rounds, having more flexibility is vital, Logsdon added. "You have to figure out the percentage before the fight," he said. "With LOS-MP you have more options from one round ... And you have greater lethality than with the current set."
If funded for the 2008 fiscal year, the munition could be fielded as early as 2010 or 2011, he said. The program is vying against other projects for funds, Cardell said. "There's a lot of competition."