OK... heres an update. all of my parts have NSF-PW on them including the back cap with the exception of the 3" to 2" which is partially over the 3" pipe. Any other safe recommendations for a PSI rating i can be comfortable with? I still have not had it up past 45-50ish.

I just built my first pneumatic cannon and want to be as safe as possible with it because im doing this just to have good ol' backyard fun with the kids and don't want anyone to get hurt. The reservoir is constructed of a 24" x 3" PVC pressure rated at like 240. The cap on the back side is also SCH....