Well, I bought the entire set recently and it is different than watching on TV; it's slower. I am just done with season 2 and I could have sworn they had the P-90s by now but they don't. I don't need to know which episode or the like because I have the disks and will eventually reach the season. So, when do they switch over? Thanks
P90s are the sub-machine guns O'Neill and Carter carry. They start off with H&K MP5s. I'm sure a more knowledgeable gun fetishist will chip in ETA: ah, oblivious as in don't care rather than don't know.
There was one episodes where O'Neill recommends them (I think one of the Unas episodes), and they just keep them after that.