The techs at my local proshop fixed the leak. They told me that I was not putting enough grease on my bolt and it was deteriorating the o-rings and possibly the bolt cap. I don't understand because I put a lot of grease on my bolt (or I suppose I do) but it's not slick lube; it's old DOW 33 grease. Does the kind of grease used in a gun really affect the air seals around the bolt?
Oh and thanks everyone for helping me with my gun-leak issue.