Its the same thing
The 7mm AM is not the same as the 7mm-338 Lapua Improved. Performance is similiar but certainly not the same.
Also, the 1200 round barrel life is a bit optomistic. Possible but you would really baby the barrel and it would greatly depend on what bullet is being used. A thin jacketed match bullet would likely loose accuracy well before this point. A hard bullet such as a 160 gr Accubond or the heavier jacketed SMK in 175 gr weights can usually handle a worn barrel just fine.
I do not recommend fireforming with corn meal in a good barrel. Over time it WILL cause extra throat wear. This is why I set up to offer formed cases to my customers with 7mm AM rifles. My Dad is in charge of this and he charges $85 per 100 cases for labor and componants.
Just for everyones information, the 7mm AM reamers are not available to the public at this time. Again the 7mm-338 Lapua is very similiar but certainly not the same as the 7mm AM.
Performance size, in a 30" barrel length you can expect to see 3300 fps with the 200 gr ULD RBBT(bullets velocity ceiling), +3500 fps with the 175 gr SMK with a custom receiver designed for the Lapua(not Rem 700), and pushing 3600 fps with the 160 gr Accubond.
My personal light weight 7mm AM is one of my very early rifles built on a converted Rem 700 which I do not offer any more. That said, its currently driving the 175 gr SMK to 3450 fps.