Need a little help

[UFC Fan 81]

I completed the game on hard and I am going back and finishing up the side missions. All I have left is pony express, poker missions(which I could use some hints on if anyone knows of any) and collect all weapons which is where my question comes in. I have 19 of 20 weapons collected anyone have any idea which one I could have missed, because I thought you got them all as you followed the story, or is there something else I need to do to get it?

[Deyankees1]

You could check the achievement guide its the best bet you have. I have the game but havent played it it's just sitting around.

http://www.xbox360achievements.org/guide.php?gameID=66

[UFC Fan 81]

You are correct...I misread the achievement guide when I first read it...I thought it said that you should get every weapon in one playthrough, I didn't see the part about you get one for clearing all side missions.....Sorry for the needless post and thanks for the help.