I have a Bushmaster V-match carbine upper.  The new Vortex I just got will not thread on.  When I compare the threading of the birdcage I used and the Vortex, it appears that the Vortex has finer threading.  The hole is slightly larger than the birdcage hole.  A .357sig slug will fit perfectly in between the ENDS of the prongs.  A spent .223 casing will fit all the way through the Vortex and almost hang by the brass rim, in the birdcage, a spent brass will only fit up to the cartridge throating.  Was a different size vortex put into the wrong package? or is my Bushy not 1/2 x 28?  I'm currently awaiting a reply from Bushmaster as well.

Quoted: I have a Bushmaster V-match carbine upper.  The new Vortex I just got will not thread on.  When I compare the threading of the birdcage I used and the Vortex, it appears that the Vortex has finer threading.  The hole is slightly larger than the birdcage hole.  A .357sig slug will fit perfectly in between the ENDS of the prongs.  A spent .223 casing will fit all the way through the Vortex and almost hang by the brass rim, in the birdcage, a spent brass will only fit up to the cartridge throating.  Was a different size vortex put into the wrong package? or is my Bushy not 1/2 x 28?  I'm currently awaiting a reply from Bushmaster as well.

I would think so.

AFAIK all Bushmaster's .223 rifles are threated with 1/2x28. Maybe you got a Vortex for .308 rifles. Send it back and have it replaced with a .223 Vortex.

I recently had this happen, i figured it was for a 9mm due to its size and hole diameter.

Just send it back.

Alright, it's going back for another. I really think it's a 9mm. Bushmaster told me there was "no way" my barrel was anything other than 1/2 x 28, but the 9mm is 1/2 x 36. Plus the hole is bigger than I thought at first. Thanks for the comfirmations guys!