When you shop for a bowl, be sure to check the restriction before buying. If it's larger than the tip of a ballpoint pen, it's too big.
To correctly pack a bowl, start by tearing off a piece of bud that's juat large enough to cover the restriction (a "nug plug") and place it gently at the bottom of the bowl. Don't press it into the hole, or air won't be able to flow around it. Then layer ground flower on top of the nug plug until it's level with the lip of the bowl. You can press the flower gently down to fill in air pockets, but be careful not to over press it or it'll be defficult to smoke. The flower should be fluffy, not dense.
We're happy to say all GRAV pipes are designed to catch ash and prevent Scooby snacking.