I shot them in 2's with an Ext. Briley Imp. Mod ported tube and a Ext. Briley Mod. non-ported and didn't care for them nor did I have any problems with a ported tube. Only shot about 2/3rds of the box and gave them to my buddy and went back to my Hevi-Metal 2's and was wackn n stackn em again. Just my experience though.