I never said it was wobbling on its own. The movement I get is from direct pressure on the can itself...like me pushing lightly, or the weight of the gun as the butt is on the ground and the suppressor is resting on the wall. I does not effect performance. I just don't like the fact that I can move it. I haven't measured it, but I would have to say the end of the suppressor will move 1/8" off center in all directions. I really think I'd blow the end cap off if I were to shoot it while it was off center.
I have a SWR Trident 3-lug QD as well. It has a very very small amount of play. It doesn't concern me at all. I went with your QD because I use this on mulitple platforms. Two of which have a SD look where the barrel shroud covers the end of the barrel. I wanted the QD so I could always have the threads protected (PITA to take on/off with the shroud in place).
I hope you don't think I'm bashing your product here. You wanted user feedback and that is what I am giving. I really think stainless is the way to go. Like I said earlier, your suppressor performs great. I just think a suppressor should be solidly mounted (Nielsen device and all). What concerns me is blowing it up if I were using a wall, post, sandbag, or some kind of support that came in contact with the suppressor. Oh, and I think you're right about going with tighter tolerences. The carbon build up is already noticable in the "loose" design. It became gritty fast. It would most likely end up frozen on the platform.
Maybe I just need a new spring. I'm sure the new spring would make it harder to move. Still, I think that movement is going to be there...new spring or not.
Edited for grammer.