Need help on WSM conversion

I have a 110 (stagger feed) that was a 243. I turned/threaded a 300 WSM barrel to fit and installed the barrel and mag bolt face.
I need help on how to get it to feed. The original 243 mag would not allow the fatter WSM case into the mag box. I opened both sides of the box. The first one fed fine when I pulled the bolt back to extract-eject, the next 2 rounds would pop out of the mag box. I bought a WSM mag box and I am having the same problem - the feed lips are too narrow to get a WSM case into the mag box. On top of that, now the boltface hits the WSM magbox lips and will not allow the bolt to close.

I need advice as I would like to get this up and running.

I did this same thing but went from 243 to 270 wsm did not have any problem.
but what you have now you need to file top of the lips down so they don't hit your bolt
do not spread them wider.

Got it up and running. Thanx a bunch.

Just curious,

Which bolthead did you use for this WSM conversion?
Did you have to make any other modifications?

I am thinking about converting a Stevens Model 200 in 270Win to 270WSM.

Thanks,
Charlie

Mag bolt head and barrel is all you need

Thanks,
Charlie