150,000 first week
300,000 first month

140,00 first week

220,00 first month

I will give it the benefit of the brand (Even though My Summer Holiday did not do so well), and say:

200k
300k

40,000 First Week
100,000 First Month

90k first week

180k first month

Wow, weren't people predicting this game would sell hundreds of thousands of PS3s just a few months ago?

90k first week

200k first month

Gundam Musou is more a hardcore game, and HSG is more a casual game.
Call me crazy, but these are my expectations:

First Week- 70k
First Month-150k

Big games like Mario party 8 and Gundam Wii can take a lot of HSG momentum, specially MP8 which is a casual game like HSG.
I actually expect HSG to sell more in the future, when PS3 is far more accesible.

Hmmm...I may be a bit on the high side but all the other games in the series performed well so I will say:

First Week- 175k
First Month- 270k

First Week - 135k
First Month - 240k