I just got a reply from PullRite today that said
Thanks for your email. You mentioned you had adjusted the forward stop and that it didn't do anything. I'm not sure how tightly you have that adjusted, but it should be snug enough that is very hard to move the hitch plate forward and back on the silver way tubes. Snug enough that you have to be in the back of the truck with both hands on either side of that hitch plate putting some muscle into it to pop it out of forward.
If it is that snug, then I would suggest checking where your trailer brakes are set. You should be able to feel without a doubt that the trailer is what's doing the stopping, not the truck. Keeping in mind that the trailer brakes won't have enough time to activate at slow stops and starts and or in stop and go traffic. In that instance, you will feel more chucking.
There will always be some kind of movement at that point, and if checking these things and adjusting if needed doesn't not make a difference, let us know and we try to diagnose things further
So i don't think I have it anywhere near tight enough because if I take a corner pretty hard or stop without the trailer, the hitch slams around. I'm going to tighten and see what happens.