Just a note or two on the Abrams.
1) Someone metioned the 120mm as the big factor, I would just like to say that personally I like the 105mm just a little bit more. It was on the M1 and M1-IP. More ammo, more ammo types, quicker for the loader to reload (lighter rounds)and more room for poggy bait in the ready ammo rack. Same gun that was on the M-60 (see USMC GW1)
2) Borg spotting that has been metioned is standard at the company level for the M1A2. If one tank targets an object then every other tank in that company will also have it targeted (range, bearing, and grid coord). This might even be improved on with the M1A2-SEP up to batt. or brigd level which would then get the red legs involed. I know one tactic we toyed with was using the CITV as spotter and just sitting behind a hill and call in arty on anything that moved never even exposing ourselves to direct fire. That make it a bad day to be a crunchy no matter what type of AT eapon you have.
3) As for tanks that could match the M1's the new German Leo 2A6 that they have exported scared the MRE's out me. And the (I'm going to screw up the spelling) Merkava 1,2, and 3 would just make me take my ball and go home, no way to attack them and drive away, walk maybe crawl yes. The real wild card is the tank that India is working on don't know much about it.
