Challenger 2 is equipped with an L30 gun
Wrong. The gun is
designated L30 (or more accurately, the L30A1 is in use today), it is longer than 30 calibers.
I wouldn't even consider the Chally 2 until the gun problem is fixed. The UK does not have the resources alone to develop sophisticated ammo types in competition with the Rheinmetal smoothbore (developed by Germany, the USA, Israel, South Africa and loads of commercial entities) for their rifled L30. While the HESH has its advantages as a GP round, its increasingly obsolete against modern armour. There has been a decision, or at least a suggestion, that the Rheinmetall L44 or L55 should be implemented into the Chally, wich would bring it up to speed. But then there is the problem of internal redesign, mainly because the Chally has uses separet propellant bags instead of unitary cartridges... the entire ammunition stowage system has to be redesigned...
As for deciding wich is better between the M1A2 and Leo 2A5 (the most modern types in large scale service), its mainly a matter of taste. They are both very much more similar than different, both being based on a failed co-development experience by the US and Germany.
I prefer the Leo 2A5, because of its "diesel" (wich is developed from a 5000hp boat engine, so it gives a
very explosive 1500hp, somewhat equalizing it with the turbine on the Abrams), wich is cheaper logistically both to keep fueled and going. Those gasturbines are damn expensive, even if they break down somewhat more rarely once they do it does costs a pretty penny to replace the powerpack.
The turbine always work on "full rev", so the Abrams burn huge amounts of fuel even idling. This is supposed to be rectified by carrying another APU-turbine to supply electricity for electrical systems and the turret when stationary. Here is were the "easier to maintain" issue starts to become clouded. While the engine alone is "simpler", its nature has forced the inclusion of another system, itself demanding additional maintenance.
It seems that the placement of the APU may have been poor, as several of the Abrams lost to fire in Iraq has had their fires started in the area where the APU is mounted, there is supposedly a "field expedient" fix for this, but wether it is fully effective I can't guess.
The gastubine also has a tendency slightly larger than the diesel to choke if driving through a water obstacle as well. This would be related to its need for greater airflow and quite logical, so I find these claims to be credible, or at least very possible.
The Abrams carries ALL its ammo in the rear-turret bulkhead, while Leo 2 carries some rounds in the hull, this would give the Abrams somewhat of an advantage in crew survivability. But then again the hull-based stowage area on the Leo is armed as well (although with no blow-out panels), so crew
should in most cases be able to escape the vehicle before a brew-up in a worst case scenario with the hull stowage area penetrated.
If we bring in the Merkava 4 things start to get difficult. The all-aspect armouring seems to be greater, but the system in all is rather unknown (ie not disclosed by the IDF), so its rather a wild-card IMHO.
The most modern Russian systems (short of Black Eagle and T-95 wich are prototypes and largely unknowns), mainly the T-80UK and T-90M still has that bad old autoloader (although updated) wich nearly guarantees a catastrophic KK brewup once penetrated. The autoloader also severely limits the possibility to use long-rod penetrators limiting the effectiveness of teh gun. The gunbarrel is lightweight and wears out much faster than the Western equivalent. Additionally they are maintenace demanding contrary to popular mythology, engines and the drive train wears out much more quickly. therefore although the tanks may be cheaper to buy, they are more expensive to maintain and train on.
Armor-wise they have nifty gee-whiz equipment like Kontakt-5 advanced ERA and active defense systems like ARENA. The problem is that these systems most likely aren't foolproof to any extent and really unproven. It doesn't look like any of the systems protected the T-90's used by Russia in Chechnya from LAW's and RPG's for instance.
In Chechnya another issue materialized. Due to the autolaoader the gun on Russian tanks are capable of less lower angles of elevation and depression, limiting their usefulness in FIBUA even more.
And AG3 is the standard weapon in Norway, altough I believe they now buy a newer model (G4?). This is the story of Norways defensive equipment; handful of F16 w/o night attack capabilities, a navy that has been ancered up in harbour because of low funding, a handful of TOWII as our main AT weapon....Our neighbours can feel safe [:)]
