what breech plug thread on a knight 12ga barrel?

[quinnconner]

I just bought a knight inline 12ga barrel on ebay.I am going to change it to either an under-hammer style or else a side-lock type of gun.I am wondering what size and what thread the breechplug would be.It has the choke tube with it and should make a really nice 12 smoothbore for me.I can go to blue grouse and get set up for about $170. I have a nice curly maple half stock that I may fit it into and go with a side lock.Aint sure yet.I got the barrel for $34 plus shipping.