I think you have to beat (complete) all the achievements for the medic.

U achieve them
theres 36 new achivments
every 12 u get a wepon

Thx for the help but there are two questions left
1.How to make the achievement where you have to charge two friends?
2.How to make the archievent where you to send the enemy a picture where you are luaghing about his pices?

thx for help again

1. First, you take toggleheal off if you have it on. Then you ubercharge someone and start switching the uber very very fast between 2 guys so you have both ubered for like 0.1 seconds.

2. Kill an enemy and then taunt above his body, AND take screenshot (with F5)

It took me hours until I understanded that I need to take screenshot too.

Yeah, you just gotta be quick

I've already done Milestone 2.
My advice: play on servers with achievementbox map. You'll get a real help at 70% of such servers.

Achievementbox maps are very useful for farming medic achivements. Usually, if you cooperate with the people inside and help them with their achievements, they will help you too.

Got the kritzkrieg and now I just need to go through all the remaining achievments to my ubersaw! :D

I had that problem but latest update fixed it :O