Russian 91 not fitting Stingray

[Sptz]

Hey guys,

I just got a new hcigar black copper and my russian 91% doesn't thread on it, I definitely don't want to force it since it's copper and it will definitely ruin it... All my other RDAs fit except for the 91%, which threads nicely on my copper hades and MVP.

Anyone has this problem?!

 

[Elizabeth Baldwin]

That's strange. Both my Russians, all my Kayfun, and my drippers all thread on my stingray fine.

 

[Sptz]

It's super weird... It's only on the stingray, I have 3 RDAs they all fit on it perfectly smooth, the russian does not as soon as I find the threads and start twisting it you feel tension :/

 

[Firestorm]

I had to sand the outside of the threads a bit on a new R91 in order to get it to thread on to my mods. I took some 600 grit sandpaper, wrapped it around the 510 connection, and gave it a few spins. That did the trick for me.