With a handle like Progun you can't be all bad. I would loosen the striker and move it forward a tiny amount and see what that does for you. Typically you loosen one screw just a little bit and take a screwdriver and lever it forward just a smidge, tighten it down and do the same to the other side. If you just shoot the screws loose and try to pull it forward you will find that it is too loose and you tend to loose where it was in the whole adjustment deal. Once you have it moved forward just a bit close the tail gate and see how it works. If it closes and latches fine now you need to make sure that it sits flush and seals properly. Sitting flush is just an eyeball thing, look at it, does it look flush? To check for proper sealing I use a piece of card stock paper and just lie it on the seal and close the tailgate. Is there a decent amount of resistance when you try to pull it out or does it just slide right on out? You can check the seal this way all the way around and adjust accordingly. If I recall correctly the latching mechanism is bolted solid and has no adjustment and the striker is adjustable and there are probably two little guide pieces on either side of the opening. These usually don't get out of line but I have seen that happen too. For the most part though if your tailgate is only half-latching on occasion you should just need to move the striker out a little bit and be done with it. Good Luck