Wait...you have a big blast? As in, not the Lanard Blast Bazooka that Nerfingnoob wrote up about?
Hmm...although I know they are very similar, the air restrictor may be somewhat different and harder to remove. I don't have one, so I don't know.
If you are afraid that the barrel will break/come off, then you had better open up the big blast, hold the barrel firmly, then yank or possibly saw off the air restrictor. If you are having trouble opening the big blast (I'm thinking that you are), I believe that you need to remove the orange ring on the front of the "shell."
If you're just scared of openiong up guns, there are only about three parts to the internals of a big blast, so you don't have to worry about messing anything up.
