243 dies and 220 cases for 6mm Win Lee Navy rd?

I have 50 new 220 cases that a very nice gentleman sent me for nothing to use in the Winchester Lee Navy rifle I have. However the necks on the 220 are about 1/4" shorter then the 6mm Navy case which makes the case overall shorter that much. But I heard that they should work if you seat the bullet long.
I re-sized the neck using a .243 FL dia. and have some 100gr 243 jacketed bullets. Does anyone see any problems in shooting these bullets and using the 243 dies for neck sizing? Of course they will all be shot in the same rifle so I will be just neck sizing the cases every time. Ray