ShariR,
Are you sure you HAVE a V2?
The trouble with the V2 pin isn't the looseness and moving block - that's a V1 problem and easy to fix.
The trouble with the V2 pin is that when they made it "floating" (spring-loaded so you don't have to adjust it for different mods or rings) something went wrong, and people are getting innacurate, changing atomizer resistance readings - it's not making a solid connection.
If you have the older V1 style pin and your block moves (this is true with MOST of them when new - from what I've heard - and it happened to me), we can talk you through that!
19 is what you see poking out the bottom, screws into 18, screws into 16 that's at the top holding your block in place.
UNSCREW 19 all the way, while kind of holding the block so it doesn't fall off.
Reach into the hole with a tiny screwdriver, and TIGHTEN 18 - again while holding the block - this time holding it tight so it won't rotate from you turning that screw.
Now put 19 back in.
That's it. You fixed the loose block, and now you can adjust the pin - turn #18 - to get your Russian to make a connection without a gap, or make a connection with a ProRing on, etc. I don't have a pix of what the new V2 pin looks like, but it involves a spring...