It's been a while since I went to the trouble, but yes you can size it straight up as I recall.
Once fired may size up just fine .
If the brass has been fired several times it can work harden and you may split some of the necks if you don't anneal them.
Most of the whelan dies have a nice tapered expander for just such uses.
A dab of case lube on the inside of the neck too can help if you remember to clean it out.
Imperial dry case neck lube works well .And no I don't fire form, check case length though.
good luck

"Camping places fix themselves in your mind as if you had spent long periods of your life in them.
You will remember a curve of your wagon track in the grass of the plain like the features of a friend."
Isak Dinesen