I have experienced the looseness. Take the atty off, turn the device upside down and firmly push it vertically down on a work surface to push it back.
To be honest I think its a good idea as if you drop the device, this apparent weak point dissipates the force and protects the 510 threading.
Sent from my GT-N7100 using Planet of the Vapes mobile app
Personally I'd prefer my mod not to bend and pull apart in my pocket but each to their own