ended up working great, good noise, awesome range compared to my last one. Thanks for the reassurance.

Im not mixing ABS and PVC, I have all PVC but the couplings are not pressure rated and im wondering if that dangerous because especially since im going from a 4 inch combustion chamber to a 1.5 inch barrel.

BigGrib I used a 4 inch coupler and then the bushing style (not the cone style) reducer for ...

Heres the deal, I built a spud gun today (which ive done before with sucess) I used sch 40 PVC, I have a 13 inch long 4 inch diameter combustion chamber, and a 1 1/2 inch diameter 42 inch long barrel. Now my problem is I wasnt able to find pressure rated connectors but the guy at home depot assured ...